Greenwich Park SE10
As the former hunting reserve of Henry VIII, Greenwich is the oldest of the Royal Parks (the others are Hyde, Green, St James', Regent's and Richmond), and it makes the most of its commanding position high on the hill above the Thames, with spectacular views over the river, the Isle of Dogs and East London. It's a beautifully diverse landscape, which varies from manicured beds to ancient woodland to the sweeping lawns in front of the Queen's House and Maritime Museum, and it's much used and valued by local residents, which explains their lack of enthusiasm its forthcoming use for London 2012 equestrian events venue (when it will be closed for over a month). They come here in large numbers to stroll, rollerblade, walk their dogs and picnic, and occasionally to join the tourists at the Royal Observatory and Planetarium. There's a small boating lake and a kids' playground at the bottom, tennis courts and a bandstand, and a separate flower gardens with lake that gives onto an enclosure for red and fallow deer. Given that there is so much to see nearby, as well as a number of decent pubs just outside the park gates and a good if pricey café within, you could be excused for deciding to make a day of it if the sun is shining.