Neatorama has this story, taken from Uncle John’s Bathroom Reader: World of Odd, about how scientists unlocked the secrets of the worst natural disaster in the history of the West African nation of Cameroon:
On the morning of August 22, 1986, a man hopped onto his bicycle and began riding from Wum, a village in Cameroon, towards the village of Nyos. On the way he noticed an antelope lying dead next to the road. Why let it go to waste? The man tied the antelope onto his bicycle and continued on. A short distance later he noticed two dead rats, and further on, a dead dog and other dead animals. He wondered if they’d all been killed by a lightening strike – when lightening hits the ground it’s not unusual for animals nearby to be killed by the shock.
Soon the man came upon a group of huts. He decided to see if anyone there knew what had happened to the animals. But as he walked up to the huts he was stunned to see dead bodies strewn everywhere. He didn’t find a single person still alive—everyone in the huts was dead. The man threw down his bicycle and ran all the way back to Wum.
By the time the man got back to the village, the first survivors of whatever it was that had struck Nyos and other nearby villages were already stumbling into Wum. Many told tales of hearing an explosion or rumbling noise in the distance, then smelling strange smells and passing out for as long as 36 hours before waking up to discover that everyone around them was dead.
Wum is in a remote part of Cameroon, so it took two days for a medical team to arrive in the area after local officials called the governor to report the strange occurrence. The doctors found a catastrophe far greater than they could have imagined: Overnight, something had killed nearly 1,800 people. Plus more than 3,000 cattle and countless wild animals, birds and insects—in short every living creature for miles around.