Together with Réunion and Rodrigues, Mauritius is part of the Mascarene Islands. This archipelago was formed in a series of undersea volcanic eruptions 8-10 million years ago, as the African plate drifted over the Réunion hotspot. They are no longer volcanically active, and the hotspot now rests under Réunion. The island of Mauritius itself is formed around a central plateau, with its highest peak in the southwest, Piton de la Petite Rivière Noire at 828 metres (2,717 ft). Around the plateau, the original crater can still be distinguished from several mountains.