In 1976, Everglades National Park was declared an International Biosphere Reserve by UNESCO,[16] which also listed the park as a World Heritage Site in 1979. The Ramsar Convention designated the Everglades a Wetland of International Importance in 1987.[17] Only three locations on Earth have appeared on all three lists: Everglades National Park, Lake Ichkeul in Tunisia, and Srebarna Lake in Bulgaria.[18]