This great Benedictine abbey was erected by William the Conqueror on the site of the Battle of Hastings—one of the most decisive turning points in English history and the last time the country was successfully invaded. A memorial stone marks the high altar, which in turn was supposedly laid on the spot where Harold II, the last Saxon king, was killed. All of this meant little to Henry VIII, who didn't spare the building from his violent dissolution of the monasteries. Today the abbey is just a ruin, but films and interactive exhibits help bring it all to life. You can also take the mile-long walk around the edge of the battlefield and see the remains of the abbey's former outbuildings.