The Galapagos Islands are an Ecuadorian province in the eastern part of the Pacific Ocean. It is an archipelago located on the equator about 1,000 km west of Ecuador. It consists of 14 larger volcanic islands. The largest island is Isabela. The archipelago has an area of 7,844 km² and about 31,000 inhabitants live there. The Galapagos were discovered by the Spanish in 1535. In the 17th and 18th centuries, pirates and travelers used the islands to replenish water supplies. In 1831, the British naturalist Charles Darwin visited the islands. He summarized his observations in the well-known and groundbreaking work " On the Origin of Species". The archipelago is known for a number of unusual animal species. It is home to marine iguanas and elephant turtles, for example. The islands have been a national park since 1934 due to their unique fauna. In 1978, the Galapagos Islands were added to the UNESCO World Heritage List.