Kensington Palace

At Queen Victoria's behest, the State Rooms of Kensington Palace were opened to the public in 1899, on her 80th birthday. Since then it's been both a private residence for the royal family and a public museum. In fact, it's where Prince William lives with the Duchess of Cambridge and their three kids. Though you won't bump into them in the hallway, a visit here is still a fascinating window into the lives of royals past and present.