At the far reaches of the Florida Keys, where the Gulf of Mexico and Atlantic Ocean meet, coral reef rises close to the surface along the west side of Loggerhead Key. Here, in Dry Tortugas National Park, the reefs host about 30 species of coral. While coral reefs are in bad shape worldwide, especially in the upper Florida Keys where runoff from development and pollution have been leading causes of decline, the reefs in the Dry Tortugas survive in relatively good health thanks to being 65 miles from the closest human population and safeguarded within a marine protected area.