We tour England's iconic Tower of London; explore an impenetrable bastion in the South of France where a controversial literary giant was jailed; and visit an ancient German castle that may hold a centuries-old secret.

Visit a British manor house that inspired the creepy masterpiece, tour a sprawling New York mansion that belonged to a Gilded Age robber baron and explore a German castle that served as a prisoner-of-war camp in World War II.

We explore an English country estate that was at the heart of a bizarre inheritance dispute, tour a colonial mansion in Virginia to understand a grisly medical experiment, and visit the ruins of a Scottish castle.

We visit a giant fortress in Scotland where a 15th-century power struggle climaxed, explore an Italian villa that housed a mysterious manuscript, and tour a upstate New York mansion.