HMS Belfast is a Edinburgh-class cruiser moored in the Thames. She was mined in 1939, served in the Battle of the North Cape on December 26, 1943 to sink the Scharnhorst and the landings at Normandy, and Korea.
The Imperial War Museum has one of the best preserved ships I've ever seen, with almost complete recreations of the ship's social history areas like crew quarters, the brig, and the medical facilities. It's a requirement for any historian to tour during their London visit.