Easter Island is a volcanic high island consisting of three extinct volcanoes: Terevaka, at an altitude of , forms the bulk of the island. Two other volcanoes (Poike and Rano Kau) form the eastern and southern headlands, giving the island its triangular shape. There are numerous lesser cones and other volcanic features: the crater Rano Raraku, the cinder cone Puna Pau and many volcanic caves (including lava tubes).