St. Thomas is the main island of the US Virgin Islands, and it offers great tax-free shopping and beautiful beaches, where visitors can go snorkeling, kayaking, horseback riding, sports fishing, sailing, windsurfing as well as surfing, playing golf and tennis. St Thomas is also home to Charlotte Amalie, the capital of U.S. Virgin Islands and a popular cruise ship port. The crescent-shaped Magen's Bay just across Charlotte Amalie is a popular beach destination. Sapphire and Coki Beaches are also lovely places to visit on St. Thomas. The island also hosts an ocean Park called Coral World, a Dutch fort built in the 1600s, and the historical Danish-built 99 steps in Charlotte Amalie.