Karthala volcano
One of the largest and most dangerous volcanoes in the world because of the possibility that water inside the volcano could be heated and explode resulting in the volcano exploding and rock raining down. Most recent activity occurred in January magma moved 7 km underground, towards a fissure in the southern side of the island, causing small earthquakes. When the volcano is calm it is a hiking destination, though supposedly a difficult two-day climb to the top.