Florida is a peninsula that is surrounded by water on three sides, with the Gulf of Mexico to the west, the Atlantic Ocean to the east, and the Straits of Florida to the south. The Florida Keys are located in the southernmost part of Florida and are surrounded by the Straits of Florida, which separate the Gulf of Mexico from the Atlantic Ocean. The Atlantic Ocean is the second-largest ocean in the world and covers approximately 20% of the Earths surface. The Florida Reef, one of the worlds largest coral reefs, stretches approximately 360 miles from the Florida Keys to the St. Lucie Inlet.