The Regent's Canal goes under Islington Hill through a 960-metre Victorian tunnel too low for people to walk — so the bargees used to lie on the roof and push with their feet against the tunnel ceiling. This walk crosses the hill on foot while the canal goes through the dark beneath.
Colebrooke Row, above the tunnel, is one of the quietest Georgian terraces in Islington. Duncan Terrace alongside it follows the old New River — the 17th-century water channel built to bring fresh water to London from Hertfordshire. Thornhill Square is the walk's surprise: a large, tree-filled square that most N1 residents never discover.