HMS Belfast is part of the Imperial War Museum, which also includes the Churchill War Rooms and IWM Duxford, which exhibits aircraft and other vessels.
HMS Belfast was built 80 years ago and was part of the Second World War and the Invasion of Normandy. Now the ship is anchored on the Thames near Tower Bridge. You can visit all nine decks of the ship which might give some idea of what it was like living at sea. Trips around the ship allow you to visit both the Operations Room and the deck of the ship, which gives a nice view of Tower Bridge and the City of London, especially when the weather is good. The ship also has an interesting location for children (recommended for children over the age of 5).
The nearest underground station is London Bridge (Northern, Jubilee), which is about 10 minutes away from HMS Belfast.