Mount Karthala, Shield volcano and Ramsar site in Comoros.

Mount Karthala is an active shield volcano in Comoros rising about 2,361 meters above sea level. Its summit holds a large caldera with multiple craters and diverse lava formations created by previous eruptions.

The first recorded eruption dates to around 1050, with the next in 1808; over twenty followed during the 19th and 20th centuries, mostly on the flanks and later inside the summit craters. The 16-18 April 2005 eruption emptied the crater lake in Choungou-Chahalé and forced 2,000 residents to evacuate. Lava was visible from Moroni on 29 May 2006. Doctor Kresten made the first ascent in 1863.

The mountain's Arabic name, Al Qirtālah, is still used alongside the Comorian forms Karthala, Kartala and Kartola. Its 1863 first ascent was made by a doctor named Kresten. On 12 November 2006 the volcano was recognised as a Ramsar site for the wetland diversity around it.

Visitors should check on current volcanic activity before ascending and use local guides who know the safest routes. The best time to hike is during drier months when the mountain is more accessible.

A 14,228-hectare tract covering the upper slopes and summit is an Important Bird Area designated by BirdLife International, protecting twelve species including the Comoros blue pigeon, Humblot's sunbird and the Karthala white-eye. The forest below is cut by fresh lava flows.