18. Castle Bluebeards
It is one of the Virgin Islands of the United States, based on St. Thomas. From what we know so far, this castle has had many different generations. 1600 was the year the Danes first built it as a stronghold to help fortify Fort Christian. But the US Government bought it in 1933 and turned it into a hotel to help promote tourism. Moreover, President Franklin D. Roosevelt also went there in 1934.