The islands in the Florida Keys span 126 miles (200 kilometers) and are home to the most extensive living coral reef in the United States, and the third largest on Earth.
Just south of the Florida peninsula, the Florida Keys National Marine Sanctuary covers 3,708 square miles (9,600 square kilometers).
The region receives more than 4 million visitors a year who come to dive, explore coral reefs and shipwrecks, and fish.
Beyond tourism, the Keys support a nearly 20-million-pound (9-million-kilogram) harvest of seafood and marine products annually. In an effort to protect the ecological and commercial resources in the park, the area was designated a national sanctuary in 1990.