St. Thomas Island is the gateway of business, cruise ships, tourism, and now dolphins of the U.S. Virgin Islands in the Caribbean. The best things this island is known for are its beaches and snorkeling spots. The U.S. Virgin Island’s territorial capital is Charlotte Amalie, a busy cruise-ship port. The cruise ship industry is big business here in the islands. There are also many historic buildings that include a 1679 watchtower called Blackbeard’s Castle, in reference to the area’s pirate history. In the St. Thomas harbor, 17th-century Fort Christian is now a local-history museum and fun place to visit.