Richmond Castle has a commanding position on a rocky promontory high over the river Swale. Its entrance, though, is in the town centre. The castle was built by Alan the Red in 1070 and the keep was added about a century later. There are stunning views over the town and countryside from the top of the keep, which is remarkably intact. Though largely ruined, the castle was in use until relatively recently. 16 'conscientious objectors' were imprisoned there during WW1 for refusing to fight and were subsequently sentenced to death. There's an interesting little garden too, 'the Cockpit Garden'.