Top 20 Most Impressive Underground Wonders in the World

Reed Flute Cave, existing for millions of years, has become a famous tourist destination in Guilin, Quangxi Province, China. Inside the cave is a dazzling, mystical world of limestone formations illuminated by colorful lights. Here, visitors have the opportunity to admire over 70 rock paintings dating back to the Tang Dynasty (year 792 AD). As one of the enchanting karst caves, it is a top-notch attraction in Guilin, named after the lush reeds growing outside the entrance. However, in contrast to the vibrant nature outside, the inside of Quan Nham Cave is a silent, magical world with an underground river and natural limestone formations resembling a fairyland.

The cave is named after the type of reed growing outside, which can be made into flutes. Reed Flute Cave is filled with a large number of stalactites, stalagmites, and other rock formations. Inside, there are over 70 ink inscriptions, possibly dating back to around 792 AD during the Tang Dynasty. These ancient inscriptions tell us that it has been an attraction in Guilin since ancient times. It was rediscovered in the 1940s by a group of refugees fleeing from the Japanese army. Today, artificial multi-colored lights illuminate the cave.

The renowned dormant volcano Thrihnukagigur in Iceland has been inactive for 4,000 years. The lava streams within the volcano have receded, leaving behind colorful mineral caves that appear surreal today. After crossing a vast lava field, visitors can explore this extraordinary volcanic cave system using specially designed cable cars. Þríhnúkagígur is a dormant volcano within the Brennisteinsfjöll volcanic system near Reykjavík, Iceland. Covering an area of 3,270 m2 and a depth of 213 meters, it hasn't erupted in the last 4000 years. Discovered in 1974 by cave explorer Árni B Stefánsson, it opened for tourism in 2012.

This is the only volcano on Earth where visitors can descend safely into the magma chamber using an elevator. The magma chamber, presumed to be completely drained and sealed, revealed cracks beneath the surface, surprising most scientists. In August 2015, members of the Icelandic band Kaleo and fourteen support staff descended into the magma chamber and recorded a live performance of their song 'Way Down We Go.' In 2016, the Secret Solstice music festival announced that alternative rock musician Chino Moreno of Deftones would perform the first public concert inside a volcano's magma chamber.

Nestled near the eastern border of the Chapada Diamantina mountain range, north of Andarai in Brazil, Poco Encantado (Celestial Well) is a deep underground pool with a natural skylight opening to the Bahian forest above. From April to September each year, sunlight penetrates, casting an enchanting azure hue to the water in the mysterious lake. With a renowned history, once a diamond mining site in the mid-19th century, Chapada Diamantina also harbors countless vibrant wild landscapes. For this reason, Chapada Diamantina has attracted hundreds of thousands of international and local tourists for exploration since its creation in 1980.

The Chapada Diamantina National Park boasts several beautiful lakes, but the most prominent is perhaps Poco Encantado (Enchanted Well). Also known as the Fairy Well, a legend tells that in 1940, some people discovered the cave and Poco Encantado. Upon reaching the lake, they were mesmerized by its crystal-clear, captivatingly green water. One person from the group brought back a bit of water to show friends. However, upon leaving the cave, the water surprisingly lost its mysterious green color. This led many to believe that the water in Poco Encantado was 'enchanted,' hence its name, the Fairy Well.

Located on Palawan Island in the Philippines, Puerto Princesa is the longest underground river in the world. Flowing into the East Sea through a 24km-long cave system, the surrounding national park is UNESCO-recognized for its diverse ecosystem, including 800 plant species, 165 bird species, and 30 mammal species. The Puerto Princesa Subterranean River National Park is a national park located about 50 km north of the city of Puerto Princesa, Palawan, Philippines. This national park is located in the Saint Paul Mountain Range on the northern coast of Palawan Island, adjacent to St Paul Bay to the north and Babuyan River to the east. The city government of Puerto Princesa has managed this national park since 1992. The national park was listed as a UNESCO World Heritage Site in 1999, is one of the New Seven Wonders of Nature since 2012, and is also an internationally significant wetland area under the Ramsar Convention since 2012.

The national park features stunning karst limestone landscapes. St. Paul's limestone cave stretches over 24 km underground, including a section of the 8.2 km-long Cabayugan River. The river flows through the cave before emptying into the West Philippine Sea. Boat travel is possible for about 4.3 km from the sea into the cave. The cave includes large stalactites and stalagmites and is one of the largest caves in the world.[3] The river's downstream portion is 6 km from the sea, influenced by the tide. Until the discovery of the Yucatan Peninsula's underground river in Mexico in 2007, Puerto Princesa held the record for the world's longest underground river. The national park comprises a range of forest types representing eight out of thirteen forest types found in tropical Asia, specifically, dipterocarp forests on ultramafic soils, dipterocarp forests on limestone soils, montane forests, freshwater swamp forests, lowland evergreen tropical forests, riparian forests, tropical heath forests, and mangrove forests. There are 800 plant species from 300 genera and 100 families. Some notable species present in lowland forest areas include Dracontomelon dao, Narra, Cow's hoof, Ranggu, Feathered fern...

Được phát hiện vào đầu thế kỉ thứ 13, mỏ muối Turda ở Romania ban đầu đơn thuần chỉ dùng để khai thác thứ tài nguyên được ví như vàng trắng vào thời điểm đó. Hiện tại, nơi đây đã trở thành bảo tàng ngầm và trung tâm giải trí với sân golf mini, vòng đu quay hay hồ nhân tạo có thể chèo thuyền. Turda là một trong mỏ muối cổ nhất thế giới được cải tạo và xây dựng thành một công viên giải trí với rất nhiều trò chơi hấp dẫn. Mỏ muối này có độ sâu 100m. Khi đến đây, du khách sẽ được duy chuyển bằng thang máy và sẽ nhìn thấy được khuôn viên mỏ muối. Thư giãn trong những không gian có thiết kế mới lạ làm du khách thích thú và có cảm giác như đang ở ngoài vũ trụ.

Muối lần đầu tiên được chiết xuất ở đây trong thời cổ đại. Mỏ liên tục sản xuất muối ăn từ thời Trung cổ, mỏ lần đầu tiên được nhắc đến vào năm 1075, đến đầu thế kỷ 20 (1932). Văn bản đầu tiên nói rõ ràng về sự tồn tại của một mỏ muối ở Turda có từ ngày 1 tháng 5 năm 1271, do thủ tướng Hungary ban hành. Các tài liệu được lưu giữ từ thế kỷ 13 và 14 đề cập đến các mỏ muối ở Turda đề cập rằng các mỏ muối được bố trí ở vi khu vực Băile Sărate và trên sườn đông nam của Valea Sărată. Các phòng điều hành được đặt tại các vị trí của các hồ muối hiện tại từ các khu vực nói trên. Vào thế kỷ 17, các công trình khai thác muối đầu tiên bắt đầu trên sườn phía tây bắc của Valea Valea Sărată, bằng chứng là các trục trên mái vòm của căn phòng Terezia. Ngay sau đó, mỏ Sfântul Anton được khai trương, nơi hoạt động khai thác tiếp tục cho đến nửa đầu thế kỷ 20.

In the late 1950s, the U.S. government requested the owners of the Greenbrier hotel to allow the construction of an emergency bunker beneath the hotel to serve as the national congressional headquarters in case of nuclear war. Therefore, visitors will have the opportunity to see the storage of 25 tons of explosives, dormitories, a hospital, and decontamination rooms. Built in 1967, designed by architect Alfred Easton Poor, with the purpose of being a shelter in the event of a nuclear war, it is now abandoned. The bunker was designed for a family of 5, allowing them to isolate from the outside world, avoiding contact with radioactive dust. The front wall is more than 0.9 meters thick, the roof panel is between 0.6 to 0.78 meters thick, and the concrete floor is 0.66 meters thick.

Everything inside the bunker is still relatively intact. In the photo is a large black container of oxygen placed in one of the rooms in the bunker. After years of abandonment, the bunker is open to urban explorers for visits. Food including butter, salt, and sugar is still present where they were originally placed. The traces of time can be seen through the corrosion of metal, and food labels peeling off. The bunker is reinforced with industrial-grade shock absorbers to withstand shocks from nuclear explosions. A 200 kW power generator is also installed here. Additionally, the bunker has a ventilation system with a radiation filter to prevent nuclear fallout.

The Waitomo Glowworm Cave in the North Island of New Zealand is famous for numerous glowworms emitting a magical light. Anyone who steps foot here for the first time must be amazed by the mystical beauty, like stars shining underground. This sparkling and enchanting limestone cave is the habitat of hundreds of thousands of glowworms, illuminating the cave whether it's night or day. Glowworms are creatures that prefer darkness, usually active at night, and it is during the dark hours that we can see the light they emit. The Waitomo Glowworm Cave is an ideal living place for glowworms with its darkness and humidity, featuring horizontal ceilings where they can weave their prey-trapping threads.

Although only discovered and explored in 1940, scientists believe it to be around 30 million years old. In the past, many thought the Waitomo Glowworm Cave only existed in the stories and legends of the Maori tribe. The one who discovered this glowworm cave was the New Zealand explorer, Lawson Burrows. After a long period of searching, he found a small stream originating from a mountain crevice. Lawson Burrows dived and swam through the crevice, and he could not believe his eyes when he saw the beautiful and vibrant light of the glowworms appearing before him. Tourists in New Zealand can experience a boat tour down to the cave's bottom and enjoy the unique and unparalleled scenery of nature.

Situated in the heart of California's San Joaquin Valley amid some of the nation's wealthiest farmlands, Fresno boasts a unique sight crafted by a visionary man. Forestiere Underground Gardens has thrived within the Forestiere family for over a century since its creator embarked on its construction. Declared California Landmark №916, the Forestiere family generously shares this gem in the desert with the public. The following images have been used with the Forestiere family's permission.

Originally intending to plant trees and vines, Forestiere acquired a plot of land. He quickly realized his land parcel included a solid hardpan rock formation. Undeterred and desperate to escape the scorching heat of summer, Forestiere altered his plans and created a remarkable subterranean oasis that he envisioned turning into a public spa. He spent 40 years carving out from the rock mass an underground network comprising over a hundred chambers, courtyards, arbors, rooms, and pathways that became his home. Little did he know that thousands of tourists would come to visit and marvel at his ingenious creation over a century after he began building it.

Discover a unique religious belief in San Clemente, a Holy Cathedral Palace built from the 12th century on the foundation of a church dating back to the 4th century in Italy. Below ground lies the Capuchin crypt, where in a 10-minute tour, you can witness around 4,000 sets of skeletal remains of monks intricately arranged as celestial decorations, forming archways, clusters of lights, or bookshelves. A holy cathedral palace is a special honorary title bestowed by the Pope on certain churches or sacred sites based on their ancient character, historical significance, and spiritual importance to the Roman Catholic Church. While most cathedral palaces are large or ancient architectural churches, not every cathedral church is a cathedral palace.

Most cathedral palaces in Catholicism are grand or ancient churches. The layout of these structures often resembles a cruciform (symbolizing Jesus Christ), consisting of three main sections: the nave, the congregation area, and the sanctuary. Inside, they house the remains of martyrs, saints, significant figures, or valuable Catholic artworks. Currently, the Catholic Church divides cathedral palaces into two types: major cathedral palaces, a title reserved for four renowned cathedral palaces under the Pope's jurisdiction, including the Archbasilica of Saint John Lateran, Saint Peter's Basilica, Notre-Dame Cathedral, and Saint Paul Outside the Walls. Only the Archbasilica of Saint John Lateran holds the title of 'Archbasilica,' considered the highest-ranked church in the Church and regarded as the mother church of all churches worldwide.

Coober Pedy in Australia is the only underground town in the world with over 4,000 residents. The outdoor temperature here is consistently high, forcing people to build homes underground to escape the heat. This area experiences temperatures of up to 45 degrees Celsius and frequently faces sandstorms. Coober Pedy is a small town located in the northern part of South Australia, 850 km away from Adelaide. The town was originally named after the European explorer John McDouall Stuart, who first set foot in this area in 1858. It was later renamed Coober Pedy in 1920, in the language of the local indigenous people, meaning 'white man's hole.'

Coober Pedy is a town in northern South Australia. It is known as the opal capital of the world due to the large opal production here. The population in 2011 was 1695 people. Coober Pedy is famous for its underground structures, where most residents live beneath the surface, constructing churches, restaurants, and hotels. Residents live underground to escape the harsh desert climate with glaring sunlight. The name Coober Pedy originates from the local indigenous term 'kupa piti,' meaning 'white man's hole underground.'

The underground rooms in London served as the nerve center of the United Kingdom during World War II. From 1939 to 1945, these underground rooms were the meeting place for Prime Minister Winston Churchill and the ministers. Today, it is part of the Churchill Museum, preserving many artifacts from that era, including maps, large-scale charts, and the rotating chair where Churchill often sat.

According to data collected by the research group at Newcastle University (UK), nearly 1,000 gyms, 376 private swimming pools, 456 home theaters, 381 wine cellars, and 115 maid's rooms were mentioned in the approved plans for underground floors in 7 areas: Kensington and Chelsea, Westminster, Hammersmith and Fulham, Haringey, Camden, Islington, Wandsworth during the period 2008 - 2017. Other facilities include 547 media entertainment rooms, 340 gaming relaxation rooms, 242 sauna rooms, 63 parking spaces, and a car museum. Even an artificial beach is allowed to be built underground.

The Dambulla Cave Temple, also known as the Golden Temple of Dambulla, is a UNESCO-recognized World Heritage site located in the heart of Sri Lanka. Situated approximately 148 km east of Colombo, 72 km north of Kandy, and 43 km north of Matale, it is the largest and best-preserved cave temple complex in Sri Lanka. The stone towers rise 160 meters above the surrounding plains, and there are over 80 recorded caves. The main attractions include 5 caves containing statues and paintings, mostly related to Lord Buddha and his life. There are a total of 153 Buddha statues, 3 statues of Sri Lankan kings, and 4 statues of gods and goddesses. Later, statues of two Hindu deities, Vishnu and Ganesha, were added.

The mural paintings cover a total area of 2,100 square meters. Depictions on the cave walls include the temptation of Mara, and the first sermon of Lord Buddha. The prehistoric people of Sri Lanka lived in these caves before Buddhism arrived, as evidenced by burial sites with human remains dating back approximately 2700 years in the surrounding area, at Ibbankatuwa near the Dambulla cave complex. This cave complex dates back to the 1st century BCE, consisting of 5 caves beneath a large overhanging rock, carved with a drip line to keep the interiors dry. In 1938, architectural enhancements included rows of columns and an entrance. Inside the caves, the cave ceiling is painted with intricate religious imagery. There are images of Lord Buddha and Bodhisattvas, as well as other gods and goddesses.

Mayakovskaya Station in Moscow, Russia, is considered one of the most beautiful subway stations in the world. This station is adorned with granite, stainless steel, and lights hidden behind vaults designed by artist Aleksandr Deyneka. When traveling through European countries, you may be familiar with subway stations. However, Moscow's subway system is regarded as the most beautiful, with a history dating back to 1935 and still in operation today. The subway network is extensive, covering almost the entire capital of Russia. Specifically, Moscow's subway system has 12 lines, a total length of 313.1 km, and 188 stations. Each day, the Moscow subway system transports up to 6.8 million passengers.

The Moscow subway stations are divided into two styles: classic and modern. Each subway station is considered a unique architectural masterpiece, resembling a museum with its distinctive features and ambiance. Many subway stations in Moscow, within the subway system, including 5 famous ones, are worth visiting and admiring.

Kaymakli, a subterranean city located approximately 20 km from the center of Kaymakli city in the central region of Anatolia, Turkey. First opened to tourists in 1964, the area is about 19 km from Nevşehir province, on the Nevşehir-Niğde road. The ancient name is Enegup. The caves may have been first constructed in soft volcanic rock by the Phrygians, an Indo-European people, in the 8th-7th centuries BCE, according to the Turkish Ministry of Culture. Built around the 6th to the 10th century CE.

The Subterranean City of Kaymakli covers an extensive area of 2.5km2, consisting of multiple underground levels with structures such as bedrooms, kitchens, churches, burial chambers, storage rooms, and wine production facilities. The entrance to the city is a tunnel dug beneath the basalt rock (a type of rock formed by volcanic eruption), connecting to the main corridor over 15m wide. On the left, there are storage rooms and workshops, while on the right, there are community activity areas. From here, small corridors lead to charming and vibrant rooms carved deep into the tuff rock layers (a type of rock formed from volcanic ash and fragments). These rooms are colorful and lively.

Graz is the capital of the Steiermark state and the second-largest city in Austria after Vienna. As of January 1, 2019, Graz has a population of 328,276 people (with 292,269 registered residents). In 2015, the population of the Graz metropolitan area was 633,168 people. Graz has a long-standing tradition as a major educational center, with four colleges and four universities, totaling 60,000 students. Its historic center (Altstadt) is one of the best-preserved city centers in Central Europe. Politically and culturally, Graz has been an important center for Slovenes and Croats for centuries, more so than the current capitals of Ljubljana in Slovenia and Zagreb in Croatia.

In 1999, the city's historic center was added to the UNESCO World Heritage List, and in 2010, it was expanded to include Eggenberg Palace on the western outskirts. The city was awarded the title of European Capital of Culture in 2003 and became a Culinary City in 2008. Dom im Berg Arch Cave is located beneath Schlossberg Castle on the mountain in Graz, Austria, formerly used as a shelter during World War II. Today, visitors can take an elevator into the cave or attend electronic music and light festivals held right inside the cave.

Paris Catacombs serve as the final resting place for the city of Paris. Originally an old mine, it was designated for skeletal remains in 1786. Stretching 1.7 km, the entrance for visitors is located at Denfert-Rochereau Square. By the late 18th century, the Innocents cemetery in Les Halles posed hygiene issues, leading to its closure on November 9, 1785. Complaints about Parisian cemeteries being overcrowded persisted due to wars and epidemics. The abandoned quarries on the outskirts were chosen to relocate the remains.

According to ritual, the relocation occurred at night with the participation of praying monks. The process began on April 7, 1786, and was completed in 1788. In 1814, the catacombs received remains from other Parisian cemeteries. Since its establishment, the Paris Catacombs have sparked curiosity. In 1787, Count Artois (future King Charles X) visited with a group of women. The following year, two ladies, Yolande de Polastron and another, also visited. In 1814, François I of Austria toured the catacombs while in Paris. In 1860, Emperor Napoleon III and his son also descended into the Paris Catacombs. After months of closure for renovations, on June 14, 2005, the catacombs reopened.

The Tomb of Qin Shi Huang was constructed over 38 years, from 246 to 208 BCE, beneath a 76-meter-high burial mound shaped like a pyramid. Its layout mimics the Qin capital of Hanyang, divided into inner and outer city areas. The inner area has a perimeter of 2.5 km, while the outer area spans 6.3 km. The main tomb is situated to the southwest of the inner city and faces east. The central burial chamber, housing the coffin and burial artifacts, serves as the focal point of the tomb's architectural ensemble. The tomb has not been fully excavated, and archaeological explorations are focused on surrounding areas, including the Terracotta Army east of the burial mound. The Terracotta Army symbolizes the guardians of the tomb and remains partially unearthed.

Above the mound, covered by a 76-meter-high earth layer, it stretches 350 meters from south to north and 354 meters from west to east. Surrounding the tomb, there are two layers of walls, with an outer wall area of 2 km², including gates. The structure consists of three levels: the outer court on top, followed by the inner court, and finally, the burial chamber. The burial chamber covers an area of around 20,000 m². In the burial chamber, a higher-than-normal mercury concentration, 280 times the standard level, has been detected. Near the burial site, within the earth layer above, approximately 300 burial pits have been discovered, containing over 50,000 significant artifacts. The Historical Records by the Han dynasty historian Sima Qian recounts the construction of Qin Shi Huang's tomb as follows: When Qin Shi Huang ascended the throne, he ordered the excavation of Mount Li. Once he unified the realm, he relocated 700,000 people to construct the tomb, dig three streams, and place the coffin. Precious items from palaces and officials were brought down for burial. Craftsmen skilled in crossbow traps were employed to shoot anyone who approached. Mercury rivers, such as the Yangtze and Yellow Rivers, were simulated using mercury.

The Škocjan Caves form a limestone cave system in the Kras region, southwest Slovenia, approximately 75 km from the capital city Ljubljana. Situated in a 413-hectare park near the town of Divača, it is one of the world's most renowned areas for studying the karst geological phenomenon and the largest underground wetland in the world. Since 1986, these caves have been recognized as a UNESCO World Heritage site. The cave system extends 6,200 m with a maximum depth of 223 m. The Reka River flows through the limestone area, disappearing within the rocks, running underground for 34 km, and then resurfaces towards the Adriatic Sea, forming the source of the Timava River. The river's flow varies seasonally, ranging from 0.03 m3 to 380 m3. The system comprises 11 caves, featuring variously colored stalactites and stalagmites, curtain-like calcite formations, and sinkholes. The largest stalactite reaches a height of 15 m. The caves also include funnel-shaped collapse dolines, chasms, natural bridges spanning approximately 5 km underground, and numerous chambers deeper than 200 m.

Geologically, these caves have existed for millions of years. Human habitation in these caves dates back to around 3000 to 1700 BCE. Ten human skeletons, along with burial objects (animal bones, pottery), were found in the Tominčeva Cave. The earliest written records related to these caves date from around 400 BCE. Greek philosopher Posidonius wrote about them (around 135 to 50 BCE). The Timava River flows through mountains, cascading into deep chasms. Various discoveries about these caves took place in the 19th century. Systematic exploration only began in 1890 with the discovery of the 'Dead Lake.' In 1904, the latest discovery was an extensive series of silent caves. However, in 1991, Slovenian cave researchers uncovered a new passage leading to the serpent lake within the present-day Marchesetti Lake.

While the end of the world or World War III hasn't materialized, it's something many Americans have planned for by creating underground shelters for decades. This includes former President John F. Kennedy, who during his presidency was inspired by the Cuban Missile Crisis to build a safe house for himself and a few thousand citizens if an attack were to occur, and what better place for that than beneath the Grand Canyon.

The Underground Hotel Cavern Suite in Arizona, USA is renowned for having the darkest and quietest room in the world. Located about 67m below the surface, the room has humidity levels at 0 and is supplied with air from the Grand Canyon cavern. This special room can accommodate up to 6 sleepers. These days, the Grand Canyon Caverns shelter is a popular tourist spot welcoming many visitors each year to explore the depth of this underground room. In fact, for just $800 a night, people can rent this luxurious underground suite for an overnight adventure to experience one of the most tranquil and pitch-dark rooms known to humanity.