In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows a pipe top and raft at Lake Nyos. The self-driven fountain (inset) can reach a height of 150 feet above the lake surface while dissipating carbon dioxide.