Gillette Castle - East Haddam, Conn.
Now listed as a state park in Connecticut, Gillette Castle was built in 1919 by William Gillette, a stage and screen actor who was famous in his time for his portrayal of Sherlock Holmes. The castle, built on 184-acre grounds overlooking the Connecticut River, was designed by Gillette himself. In 2009 alone, the park saw roughly 200,000 visitors, with half of the guests taking self-guided tours of the historic residence.

