Eilat, Israel
Credit: Jeff Rotman / Getty Images

This narrow, deep finger of the Indian Ocean boasts high biodiversity, with more than 1,200 miles of coral reef and dozens of fish species found nowhere else – plus great visibility and calm seas. Just off the shore from Eilat, the Coral Beach Nature Reserve's three-quarter-mile long coral reef, one of the northernmost in the world, is home to 100 types of coral and 650 types of fish, including butterfly fish, parrot fish, lion fish, and groupers, as well as rays and marine turtles. A number of designated underwater trails are marked by buoys. Hotels in the Coral Beach area, a few miles south of Eilat proper, offer easy access to the near-shore reef.