Regent's Canal is one of London's best long urban walks, running from Paddington through Regent's Park, Camden, Islington, Mile End, and Limehouse. Around Camden Lock it is busy and lively, with market crowds and narrowboats; farther east it becomes quieter and more industrial.
From Camden, the towpath makes an easy approach to Regent's Park and London Zoo. Downstream is less polished but still interesting, especially if you want to see a working, less ceremonial side of London. Watch for cyclists on the narrow path.