Hang Son Doong and Cu Chi Tunnels are among the wonders frequently mentioned in numerous articles on CNN (USA).
1. Son Doong – The Largest Cave in the World
Son Doong Cave, situated in Phong Nha-Ke Bang National Park, is a colossal cave formed around 2 to 5 million years ago. Over time, water flowing through the limestone region eroded and created a vast tunnel underground. In areas where the rock is softer, the ceiling collapsed, forming holes, gradually creating a magnificent cavern.

The cave is estimated to be 150 meters wide, with a ceiling soaring over 200 meters high and at least 5 kilometers long. Explorers couldn't even reach the cave's deepest point to accurately measure, but it's likened to holding an entire neighborhood of Manhattan. Apart from its impressive high ceilings adorned with sparkling stalactites, the cave system, river, and dense waterfalls deep underground give visitors a feeling of journeying to the center of the Earth.
2. Astonishing Surprises in Halong Bay
Halong Bay, a world-famous destination renowned for its magnificent limestone cave system. Despite its central location within this World Heritage Site, Surprising Cave stands out as the most spacious and stunning cave here. The entrance to the cave is 25 meters above sea level, concealed by lush foliage. Stepping into the cave, visitors are often overwhelmed, feeling like they're standing in a giant theater with an area of 12,200 square meters.

The cave is divided into 2 chambers adorned with numerous stalactites and stalagmites illuminated by rainbow-colored fluorescent lights. The cave ceiling reaches up to 30 meters and is covered with clusters of natural lights.
3. Cu Chi Tunnels
This tunnel system was constructed from the 1940s and stretches 250 kilometers underground to the Cambodian border. Cu Chi is not only a complex labyrinth underground but also a historical landmark, serving as a hideout for thousands of Vietnamese during the years of resistance against the United States.

Within these three-tiered tunnels are field hospitals, living quarters, military planning areas, storage facilities, and weapon workshops. Today, only the Ben Dinh and Ben Duoc sections are open to tourists for exploration.
4. Vinh Moc Tunnels – Quang Tri
This 2 km long underground system, though smaller than the Cu Chi Tunnels, stands as a testament to human resilience and historical significance. It served as a crucial supply route for food and weapons to Con Co Island—a pivotal point in the fight against the US. It took locals 18 months to dig these three-tiered tunnels, with the deepest level plunging 23 meters underground. Remarkably, records indicate that 17 babies were born within these historic tunnels.

5. Unveiling the Majesty of Thang Long Imperial Citadel Underground
The extensive excavation site has unearthed a rich array of artifacts spanning from the 7th to the 19th century.

Among the architectural remnants are foundations, pillars, walls, roads, and tiled floors, along with drainage systems, wells, and lotus ponds. Discoveries include bricks, pottery, stone pillars, jewelry, and even animal bones and large shell fragments used for pavement. This archaeological site within Thang Long’s ancient citadel attests to its enduring preservation beneath the earth.
6. Rediscovering the Hidden Bunker beneath Metropole Hotel
During the construction of the Bamboo Bar in August 2011, workers stumbled upon a long-forgotten underground bunker within the confines of the Metropole Hotel. Spanning 40 square meters, the bunker comprises five rooms and two corridors, impeccably preserved to this day. Verified reports suggest that American singer Joan Baez once performed here during the historic events of 1972.

In addition to this hidden bunker, the Metropole Hotel also features an exhibition area showcasing 110 years of the hotel's history along its 18-meter corridors, including 13 panels documenting the hotel's restoration journey from its early days.
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Source: Mytour Travel Guide – Via VnExpress
MytourApril 21, 2014