Mount Cameroon is the only active volcano in the country, but has erupted frequently in recent history, including seven times in the 20th century destroying plantations and parts of the surrounding landscape in 1909, 1922, 1959, 1982, 1999 and 2000. Cameroon has very active and dangerous crater lakes that accumulate and periodically release carbon dioxide causing the mass death during the Lake Nyos disaster in 1986, which killed 1700 people, as well as the deadly 1984 release at Lake Mounoun which killed 37.