Deadliest lake
Lake Nyos
2,000 people
Cameroon (Lake Nyos)

The lake responsible for the most deaths without drowning is Lake Nyos in Cameroon, west Africa, where toxic gases have claimed nearly 2,000 lives in recent decades. On one night – 21 August 1986 – between 1,600 and 1,800 people and countless animals were killed by a large natural release of carbon dioxide gas.

Scientists disagree on the source of the Lake Nyos' deadly gas. Some believe that the decomposition of organic material near the bottom of the lake causes the gas to build up, and seasonal changes in surface temperature triggers mixing of deep and shallow water, allowing the gas to be released. Because Nyos lies in the crater of an old volcano, others believe that the gas is volcanic in origin.