Greenwich Park

Greenwich Park sprawls across 183 acres of London's south-east, and it's one of those rare spots where you can actually forget you're in the city. The main draw is the Royal Observatory perched on the hill - that's where the Prime Meridian sits, dividing the world's time zones. Walk up through the park and the views across London flatten out beneath you; on a clear day you'll see all the way to St Paul's Cathedral.

The grounds themselves are properly lovely. There's formal gardens near the entrance, a paddock with grazing deer, and woodland paths that meander down towards the Thames. Kids tend to enjoy the deer and the open space for running around, though the uphill slog to the Observatory sorts out the genuine walkers from the casual strollers.

For history types, the Observatory is the real business - standing on that meridian line where east meets west never gets old, even if you've done it before. The park's also Grade I listed, dating back to the 1660s when it was redesigned as a royal park.

Allow a good three hours minimum if you want to hit the Observatory and ramble a bit; half that if you're just after a walk and some views. Spring and early summer are best - less crowded than summer proper. If you're staying at Abbey Wood Experience Freedom Glamping nearby, this is well within striking distance and worth the drive in. Free to roam the park itself, though the Observatory charges for entry.