The Galápagos Islands are an archipelago of volcanic islands in the Pacific Ocean, 906 km (563 mi) west of continental Ecuador. The Galápagos Islands and their surrounding waters form the Galápagos National Park, and the Galápagos Marine Reserve. The islands are famed for their vast number of endemic species and were studied by Charles Darwin during the voyage of the Beagle. His observations and collections contributed to the inception of Darwin’s theory of evolution by natural selection.