This 1,935-acre land and sea monument run by the National Park Service is home to numerous varieties of brightly-colored fish and coral, birds and pristine beaches, but can be reached only via a day charter boat that leaves from the Christiansted waterfront or a marina along the island's north shore. The reef that nearly surrounds the 180-acre island features an underwater snorkel trail easily accessible by novice snorkelers, as well as those with more experience. An easy hike takes visitors to the apex of this island for a panoramic view of the reef below and the turquoise sea that stretches north to St. John. Free admission.