The British monarch's official Northern Ireland residence is this rambling, two-storey late-Georgian mansion, which was built in 1797 for Wills Hill, the first Marquess of Downshire and extensively remodelled in the 1830s and '40s. Book ahead for guided tours taking in the state drawing room and dining rooms, and the Lady Grey Room where, in 2003, Tony Blair and George W Bush held talks on Iraq.
