The classical Alexander Palace, built by Quarenghi between 1792 and 1796 for the future Alexander I, is surrounded by the charming Alexander Park. Nicholas II, the last Russian tsar, was its main tenant and he made it his residence for much of his reign.
The palace is currently undergoing renovation and is closed to the public, with completion due in 2018 at the earliest.
Nicholas and his wife Alexandra cared for their haemophiliac son and heir to the Romanov throne, Alexei, within this sad palace's walls, as his empire and dynasty slowly collapsed. When the palace reopens, expect to see a number of impressive rooms (look for the huge tiger-skin carpet and an extremely ropey portrait of a young Queen Victoria).