Top 10 Mysteries, Cold Cases & Puzzles That Were Finally Solved

Or have they? For the most part, absolutely. Indeed, they have.

There’s something inherently captivating about a good puzzle—consider the classic jigsaw. Hours spent sifting through countless pieces, identifying corners, and matching colors and patterns, all leading to the satisfaction of completing the image. It’s deeply rewarding. Even when the puzzle is exceptionally large or challenging, taking days or weeks to finish, the sense of accomplishment—and perhaps relief—is immensely gratifying.

But what happens when a piece is missing? It’s not just disappointing—it’s maddening. It can spoil an evening, a vacation, or, in some cases, even strain relationships. The mysteries listed here are all incredibly complex puzzles that have finally found their missing pieces. Thanks to technological advancements, new evidence, or sheer logical reasoning, these enigmas have been resolved or, at the very least, brought into clearer focus.

10. Blue Jets

When audiences witnessed the White House obliterated by an alien spaceship's energy weapon, few realized that nature creates something strikingly similar—known as 'blue jets' or ionospheric lightning. For years, scientists were baffled by the origins of this stunning phenomenon. Now, we have a clearer understanding... kind of.

According to researchers using cameras and X-ray detectors on the International Space Station, this breathtaking atmospheric event is an upward lightning flash, often stretching 48 kilometers (30 miles) in length. The culprit? 'Blue bangs,' a series of vibrant blue bursts within massive thunderstorms. Mystery solved... or is it?

Except we still lack a definitive explanation for these 'blue bangs.'

Torsten Neubert, an atmospheric physicist, has proposed a theory: short-range electrical discharges occurring within half a mile of each other trigger these events. The intense bursts of current generate the 'blue bangs,' which in turn produce the 'blue jets.'

Or, you know, it could just be aliens.

9. How in the Sweet Hell Does the Flimsy-Looking Butterfly Actually Fly?

Birds’ flight mechanics are well understood, and studying them even paved the way for human aviation. Butterflies, on the other hand, are a different story. They resemble delicate crepe paper fluttering in the breeze. For years, scientists puzzled over how these fragile insects achieve flight, but a definitive answer remained elusive—until now.

A research team at Lund University in Sweden tested a 50-year-old theory known as the 'clap' hypothesis. Using robotic wing models, they confirmed that butterflies indeed rely on this mechanism to fly. The experiment was a success.

However, it’s not as simple as their large wings slapping together. Butterflies possess highly flexible wings, with only the tips clapping. This motion creates an 'air pocket' that enhances propulsion and enables precise directional movement.

8. Why Do Japanese Trains Keep Getting Stopped by Millipede Swarms?

In the forested mountains of Japan, trains are sometimes brought to a standstill by massive swarms of toxic millipedes. This peculiar occurrence dates back to the 1920s, making it a century-old mystery. In 1977, forestry expert Keiko Niijima proposed that this might be a cyclical event, theorizing that the millipedes migrate every eight years—a pattern similar to certain bamboo species and, more notably, cicadas.

More than four decades later, this theory has been validated. In January 2021, researchers from Shizuoka University confirmed the eight-year cycle, explaining that the migrations are driven by the millipedes seeking new, nutrient-rich feeding areas. The next question: Are these millipedes plotting global domination? Give them eight years, and we might find out.

7. When Was Money Invented?

Photo credit: Wikimedia Commons

For centuries, scholars have grappled with this historical puzzle: When did humans first start using money? Now, we have an answer—or at least a new earliest date for objects that align with our modern concept of 'money.'

Dutch researchers discovered that many Bronze Age artifacts—ring-shaped objects, ax blades, and rib-like items—were nearly identical in weight, indicating they were used as a primitive form of currency. This finding reveals that money-based trade existed in Europe as early as 5,000 years ago. However, evidence of prehistoric subprime mortgages on mud-and-straw huts remains notably absent.

6. 45-Year-Old Cold Case Solved

Once again, following high-profile cases like the Golden State Killer and the Bear Brooke murders, the team at Parabon NanoLabs has identified the culprit in another cold case. This case is among the oldest to be solved in the U.S. in recent history.

On December 27, 1975, police in Grand Junction, Colorado, discovered the body of a woman who had been tied up, assaulted, and strangled in an apartment complex. Forty-five years later, after the case had long gone cold, authorities turned to Parabon for DNA analysis, aiming to create a genetic profile of the killer.

The DNA results returned, and after cross-referencing criminal databases, police identified Jimmy Dean Duncan as the perpetrator. Duncan, who was 26 in 1975 and had been a suspect at the time, passed away in 1987. While he can never face justice for this heinous crime, the mystery of Deborah's murder has been resolved, offering some closure to her family and friends.

These breakthroughs inspire hope that cold cases may one day become rare—or even a thing of the past.

5. The Ancient Persian Army That Vanished

While individuals go missing frequently, the disappearance of entire groups is far less common (consider the Roanoke colonists who vanished in 1590). The tale of King Cambyses II and his army stands apart. In 524 BC, approximately 50,000 soldiers disappeared into the Egyptian Sahara, as if the desert had consumed them. For millennia, the story held that the army, sent to destroy the Oracle of Amun at the Siwa Oasis, was engulfed by a massive sandstorm near Luxor, burying them all beneath the sands.

In 2009, a team of Italian archaeologists uncovered bronze artifacts and human remains, suggesting the lost army's location. Did they truly perish in a colossal sandstorm, as the ancient accounts claimed? The findings, presented in a documentary (which leaned more toward Ancient Aliens than scholarly Egyptology), seemed to support this theory.

Egyptologist Olaf Kaper, commenting on the 2014 discovery, dismissed the sandstorm theory. The remains were found near a fortress once occupied by Petubastis III, an Egyptian rebel leader. Kaper believes the Persian army was ambushed and annihilated, much like the Romans in the Teutoburg Forest. The Persians' overconfidence likely led to their downfall, as they were outmaneuvered by rebels familiar with the terrain and driven by vengeance. The sandstorm myth was likely fabricated by Cambyses' successor, Darius I, to tarnish his predecessor's legacy and strengthen his own rule over Egypt.

Considering the improbability of tens of thousands perishing in a single sandstorm and applying Occam’s Razor, it’s reasonable to conclude that this ancient piece of propaganda can finally be laid to rest.

4. Geometric Problem Solved After 90 Years of Head Scratching

The conjecture, proposed by German mathematician Eduard Ott-Heinrich Keller in 1930, posits that in any tiling of Euclidean space with identically sized squares (or hypercubes in higher dimensions), at least two squares will share a full face. While proven true for dimensions up to six, the sixth dimension remained too complex to resolve.

A team from Carnegie Mellon University, with the aid of advanced computing, finally cracked the problem. After four months of programming and just 30 minutes of computation, the 90-year-old puzzle known as 'Keller’s Conjecture' was solved.

'I was thrilled when we solved it, but then I felt a bit sad that the problem was no longer there,' said John Mackey, a professor at the university.

Bet you can’t pull that off again with just a pen, paper, and an abacus, Johnny boy.

3. Who Was Jacob Klimowsky?

The Nazis' theft of art, treasures, and artifacts, along with their infamous book burnings, is widely documented. Less discussed is their destruction of cultural heritage sites, a hallmark of totalitarian regimes. Mao’s eradication of Chinese historical landmarks to reshape national identity is another stark example. The demolition of the Königsberg New Jewish Cemetery in Kaliningrad in 1938 is a lesser-known but equally tragic instance of this cultural erasure.

Opened in 1928, the cemetery featured a stunning funeral hall designed by renowned architect Erich Mendelsohn. After its destruction, it was forgotten, reduced to rubble on an overgrown plot for decades. In 2010, members of the East Prussian Jews, a Berlin-based historical society, visited the site and made an astonishing discovery: a single intact gravestone belonging to Jacob Klimowsky. This miracle soon turned into a mystery, as no records of Klimowsky or his family could be found in the area.

A decade later, after extensive research, the society managed to locate and reach out to some of Jacob’s descendants. They were unaware that their ancestor, a WWI veteran who fought for Germany, was buried in Königsberg, let alone that his gravestone was the sole surviving one. The family shared documents and photos of Jacob, enabling the society to solve the mystery and restore a piece of local heritage once thought lost forever.

2. Literary Puzzle from 1934 Finally Solved…Again

If you’re the type who can’t resist flipping to the end of a detective novel to uncover the killer without the effort of reading properly, you’ll despise the literary puzzle known as 'Cain’s Jawbone.'

Written by Edward Powys Mathers of The Observer in 1934, the puzzle is a murder mystery novella with its pages deliberately scrambled. It was solved by two individuals in the 1930s, each earning £25. Over time, 'Cain’s Jawbone' faded into obscurity, and its solution was lost. A copy was donated to Shandy Hall, a museum honoring Laurence Sterne, where the curator became the third person to crack the puzzle.

In 2019, the curator partnered with crowdfunding publisher Unbound to reissue the puzzle, offering £1,000 to anyone who could solve it within a year. Twelve people attempted the daunting challenge, but only one succeeded—the fourth person ever to solve it. BBC comedy writer John Finnemore spent four months unraveling the intricate mystery. The Laurence Sterne Trust holds the solution; if you’re up for the challenge, they’re the ones to verify your answer.

1. Missing Link of the T-Rex Identified

Tracing the complete evolutionary lineage of creatures that lived millions of years ago is no easy task—it involves extensive excavation and painstaking research, often yielding results that barely make headlines. If a 'missing link' in human ancestry were discovered, the world would go wild.

But dinosaurs? Not so much.

Fortunately for the researchers involved, the dinosaur in question is one of the most famous and beloved species—Tyrannosaurus rex. In 2019, news broke revealing the connection between the Jurassic Park icon and a smaller dinosaur discovered earlier, called Suskityrannus hazelae. This smaller predator, first unearthed in New Mexico two decades ago, predates its colossal relative by several million years. Standing at just 1 meter (3 feet) tall at the shoulder, it’s a far cry from the giant that famously terrorized a man on a toilet (Gen Z, watch the first movie—it’s the only decent one in the series).

One of the most significant findings is the similarity in arm length between the two species. The smaller tyrannosaur already had the short forelimbs and powerful jaws seen in its more famous descendant. This suggests these traits evolved while tyrannosaurs were still relatively small, which makes a lot more sense.