Colinton Dell is the south-west's secret: a steep wooded gorge cut by the Water of Leith, with an old railway running through the middle of it and a tunnel that someone had the sense to paint. The city is fifteen minutes behind you and feels much further.
Just under four kilometres, best on an afternoon with low sun reaching into the trees. Start in Colinton village, where Robert Louis Stevenson spent boyhood summers at his grandfather's manse — there's a statue of the boy and his dog by the kirk. Drop into the dell, where the river runs hard over an old mill weir and the path keeps to the water.
The set piece is the Colinton Tunnel: a hundred and forty metres of disused railway bore, painted end to end by the community with a Stevenson poem threaded through it, lit so the colour holds. Walk it slowly. Beyond, the path passes the Redhall walled garden and the ruined mills the dell once turned. End where the Union Canal sails over the valley on Telford's Slateford aqueduct — climb to the towpath and the 44 home.
