English: Artificial carbon dioxide vent in Lake Nyos, Cameroon. 2006.

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. Afterwards, engineers installed a pipe system to vent the gas from the lake. This photo shows the Lake Nyos pipe in operation. The 200-meter-long pipe is suspended from the raft and allows gas-rich water from the lake bottom to vent to the surface, where the CO₂ dissipates into the atmosphere at a controlled rate. The shed on the control raft is about 6 feet tall and the fountain is about 120 feet tall. There are no pumps involved because the CO₂ drives the fountain, just like a shaken bottle of champagne.