Exploding Killer Lakes

Are you scared yet? Via ozy:

A giant cloud of carbon dioxide bubbled up from Lake Nyos in northwestern Cameroon near the border of Nigeria on August 21, 1986, flowing into the valley below. It stripped the air of oxygen, suffocating 1,746 villagers and 3,000 animals to death.

According to the article, there are only three know lakes in the world that have the properties to cause this.  Click here for the full article.