Blackbeard's Castle is one of five National Historic Landmarks in the U.S. Virgin Islands. It is located in the city of Charlotte Amalie, on the island of St. Thomas. Built in 1679 by the Danes as a watchtower to protect the harbor as well as Fort Christian. Blackbeard's Castle was originally called Skytsborg Tower (meaning sky tower). It is located at the highest point on Government Hill. Skytsborg Tower served as a very effective vantage point for Danish soldiers to spot enemy ships. Fort Christian is at sea level, thus making it ideal for thwarting attackers with cannon fire; however, the fort itself did not provide an ideal view of incoming ships entering the harbor.
It is not known what year Skytsborg Tower took on the name of Blackbeard's Castle, but the infamous Edward Teach, commonly known as Blackbeard, did sail the Caribbean waters in the early 18th century. It has become part of the lore of the island that he used the tower as a lookout for his own purposes of piracy. It was the centerpiece of a private residence for many years, but now is surrounded by a small hotel (The Inn at Blackbeard's Castle), a pool, and a snack bar that is open when the grounds are open for tours. The restaurant closed in 2007.