Transport for London wants people to put down their Oyster cards for one weekend, and walk around London instead.
Spring Into Summer is a series of 45 free guided walks, which vary in length from 1.1 miles to 10 miles. For those who want to stay central, themes include the real West End, the riverbank from Waterloo to London Bridge and a St Paul's circular walk, which explore secret corners of the City.
Alternatively, get out and explore London's outer boroughs, with an admirable 7.5 mile ramble from Wimbledon Park to Richmond, or a less strenuous amble across Monken Hadley Common between High Barnet to Cockfosters.
A 2.2 mile walk following the route of part of the Bakerloo line ties in with TfL's Transported by Design series, celebrating the architecture of Bakerloo line stations.
Some of the walks are family-friendly, involving the likes of dragons, lions, unicorns and Goodnight Mister Tom, to keep little minds happy.
Spring Into Summer takes place 21-22 May. The walks are free but need to be booked in advance.