Réunion, officially known as the Department of Réunion, is an island in the Indian Ocean that is both an overseas department and a region of France. People from France and Madagascar settled on the island in the 17th century. Slavery was abolished when the Second Republic abolished slavery in the French colonies on December 20, 1848, which is celebrated annually on the island. Nevertheless, indentured workers continued to be brought to Réunion from places such as southern India. Since 1946 the island is a French Département. The island is 63 km in length, 45 km in width and covers an area of 2,512 km2. It is located above a hot spot in the earth's crust. A shield volcano at Reunion's eastern end, Piton de la Fournaise is over 2,631 meters high, with over 100 eruptions since 1640. Northwest of Piton de la Fournaise is Piton des Neiges volcano, the highest point on the island at 3,070 meters. Southwest of the mountain are collapsed calderas and canyons. Whereas Piton de la Fournaise is one of the most active volcanoes in the world, Piton des Neiges is dormant. Réunion is host to a variety of birds such as the White-Tailed Tropicbird, many of which are endemic to the island, such as the Réunion Harrier and the Réunion Cuckooshrike. The Panther Chameleon is the largest land animal on the island. A large part of the west coast is surrounded by coral reefs, home to sea urchins, Conger Eels and Parrot Fish. The coastal waters are also home to turtles and dolphins, and the island is also home to the world's largest cetacean population, the Humpback Whale, which makes its annual migration north from the waters of the South Pole to breed and feed during the winter months.