The Galápagos Islands sit on the Nazca tectonic plate whose eastern boundary is slowly subducting underneath the South American plate. Therefore, the oldest islands are located in the east and south of the archipelago; the western islands—closer to the hotspot—remain volcanically active and are the youngest. Española is now the remains of what was once a shield volcano, harboring an amazing array of native species. Like its neighboring islands, San Cristobal and Floreana, Española presents a high rate of endemism compared to the rest of the Galápagos.