Syon Park

The Duke of Northumberland's London home, the only surviving ducal residence and country estate in Greater London, is right out of BBC costume drama territory, down to its 40 acres of Capability Brown gardens, 200 acres of parkland and magnificent Renaissance house. Indeed, if it looks familiar, it's probably because you'll have seen it on various TV shows, most recently the Beeb's 'Great British Bake Off' and Stephen Poliakoff's drama 'Dancing on the Edge.' On occasional Sundays and holidays under-16s can visit for free (maximum of two free tickets per paying adult); in 2013 these are May 5 and 6, May 26 and 27, and daily from Sunday July 21 to Thursday August 29. Note that the house and gardens are closed from August 30 to September 7.