I've always enjoyed walking along canal towpaths. Let's face it, you've got to living in the Midlands. Big hills are far away, and you may only have half a day free... I've done the under-walked, pleasantly rural Grantham Canal (which winds from Nottingham 33 miles across the Vale of Belvoir in Leicestershire to Grantham in Lincs) and the only truly bad bit was at the Grantham end where hypodermic needles littered the path. I've also walked half the Chesterfield Canal (mmm... must do the Retford - Worksop section one day soon) and bits of the Trent & Mersey and the Llangollen (including the magnificent Pontcysyllte aqueduct over the river Dee). Not to mention the waterways of Venice and Amsterdam. But my big project is The Grand Union. It runs for nearly 150 miles from London to Birmingham and was engineered by William Jessop (1745-1814). You may not have heard of him as he was considerably more retiring than his self-publicizing contemporary Thomas Telford. It's one of those routes I've been walking haphazardly on-and-off for years. I've completed about one third of it (Birmingham's Gas Street Basin to Weedon in Northamptonshire) - sometimes doing "there-and-backs" (I don't mind at all retracing the same route) and sometimes using the train to return to the starting point. It was fun working out the logistics. Occasionally I even took a few hours off work in the afternoon - I used to be a 40,000 mile a year rep - to polish off another short stage in suit and posh shoes and with umbrella!!! Obsessed? Who, me? Anyhow, the guides to get are The Grand Union Canal Walk by Anthony Burton and Neil Curtis published by Aurum Press, or the one with the same title by C. Holmes published by Cicerone.