The surface of the earth is divided into massive tectonic plates which slowly drift across the globe. The formation of the Galápagos is intimately tied to this geographic phenomenon and the history of the Nazca tectonic plate on which they lie. The islands of the Galapagos are essentially a group of volcanic islands, formed about 3-5 million years ago as a result of these shifting tectonic plates. Volcanoes formed under the sea broke through the ocean floor and eventually emerged, rising as islands. Each island formed from a single volcano except for Isabela Island where 6 volcanoes converge from side to side, with 5 of them still being currently active (Alcedo, Cerro Azul, Darwin, Ecuador, Sierra Negra, and Wolf. Sierra Negra’s last eruption was in October of 2005).