The biggest and wildest park, if you have the time, is 30 minutes from Waterloo station, in Richmond, which was once a distinct village but has been absorbed and yuppified by the greater city. It’s more than a park—it’s a habitat: 2,500 deliriously green acres brimming with herds of deer (since the 1600s!), 144 species of birds, and 11 of Britain’s 17 bat species. Beeline to the Isabella Plantation, a 40acre woodland garden, in May for a nearly pyrotechnic display of pink rhododendrons and azaleas. The visitor center is by the square in front of Pembroke Lodge, a Georgian mansion. Even if you don’t have time to explore the whole park (no one does), you can follow the footpath on the south bank of the Thames for miles, starting by Richmond’s waterside pubs and carrying on past ancient oaks (some nearly 800 years old) until you’re ready to double back for a second pint.