In 1984 in a village in the African nation of Cameroon….

1. In 1984 in a village in the African nation of Cameroon….

2. There is a lake known as Nyos. It’s a beautiful lake that fills the cauldron of a ancient volcano. Nothing about it gives clues to the danger that rests in its deep waters.

3. On the night of the apocalypse, Ephriam Che was in his mud brick house on a cliff above Nyos. Around 9 P.M., Che heard a rumbling that sounded like a rockslide. Then a strange white mist rose from the lake. He went to bed, feeling ill.

4. At first light, Che headed downhill. Nyos had turned a dull red. He noticed the silence; the morning sounds of songbirds and insects were absent. He also saw dead animals. Frightened, he ran farther along the lake and downhill to the village. There, nearly every one of the village's 1,000 residents was dead, including his parents, siblings, aunts and uncles. It was the end of the world, or so Che believed.

5. Eye witnesses said they saw an invisible river coming down the hill knocking down brush and small trees. It traveled at about 50 mph but could not be seen.

6. All told, some 1,800 people perished around Lake Nyos. Later the killer was found to be carbon dioxide, which is not considered toxic, but its high density keeps it close to the ground causing asphyxiation (choking). Density also caused it to flow down the hillsides asphyxiating more people.

7. Scientists found the carbon dioxide had been building up over time at the bottom layer of the lake. Magma vents were pumping CO2 into the lake forming carbonic acid (H2CO3) which essentially is carbonated water. The water pressure kept it from decomposing in to CO2 gas which would float and dissipate. However, a rock slide or small earthquake triggered the carbonic acid to decompose into CO2 causing the lake to explode. To prevent build up of CO2 scientists installed pipes that reach down to the depths and trigger a release of CO2. This huge fountain is only powered by the release of CO2.