What are the most famous solved mysteries?

 On the night of 21st August 1986, people in remote villages in Northwest Cameroon were about to end one of their days. Families tucked their children safely into bed, left the remaining chores and went to sleep.

The next day, more than 1700 of them didn't wake up. They were dead. Their bodies showed no signs of visible injuries and nobody had any explanation as to how they died.

When the news of this unusual event spread, it created mass fear and panic among the locals. Villagers suspected it to be caused by the spirit of a woman that lived around the lake, while others suspected a bioweapon attack. However, the truth was far more complex and strange.

The villages were located near Lake Nyos, a lake which sat inside an old volcanic crater. For centuries underground volcanic activity had been leaking CO2 gas into its waters. The gas kept building inside it without any escape.

Lake Nyos

Then on that fateful night, maybe an earthquake or a landslide, ended up releasing all that built up gas. The exact cause remains unknown. Villagers however, heard strange noises from the lake that night.

Soon, an estimated 300000 tons of CO2 engulfed the villages like an invisible cloud. Since CO2 is heavier than air, it didn't dissipate and many villagers never got a chance to escape. They suffocated in their sleep.

A mystery that started with local folklore and a suspected bio weapon attack ended up having a scientific explanation to it. In 2001, almost 15 years after the initial disaster scientists installed pipes that now lets the gas escape safely.

What ancient mystery has been solved today

About 3,400 years ago, one of the famous "Colossi of Memnom" from Egypt began to "sing ." Yes, according to some hieroglyphics , during the sunrise, one of the statues

It began to emit a sound that lasted for minutes . The sound was described as a powerful, yet somehow mysterious, tone that slowly faded away.

Naturally, this fact has left many researchers and archaeologists perplexed.

After further investigation, it was discovered that the reason the statue was actually singing was because the heat produced in the early morning hours evaporated the dew trapped inside the cracks of the statue, causing acoustic vibrations that resonated in the Egyptian desert air.

Thus clarifying, thanks to research science, that the statue was not actually singing, but rather emitting acoustic vibrations as the water evaporated inside the cracks.

What mathematical problem was solved in an improbable way?

 In 1939, George Dantzig was a student at the University of California, Berkeley...

… And like many students, he was sometimes late.

One day, when his math class had already begun, Danzig entered class and saw two statistical problems written on the blackboard. Thinking that it was homework for the next lesson, he hurried to write them down without question. And a few days later, he gave the solution to each of these two problems.

Six weeks passed when his statistics teacher (Jerzy Neyman) visited him with unexpected news. Danzig learned that he had solved two of the most famous statistical problems that have not yet been solved.

He later said that the problems "seemed a little more difficult than usual."

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Even though the name Danzig remains relatively unknown, this anecdote has become popular over time. It may remind you of that famous scene with Matt Damon in the movie Good Will Hunting.