I discovered the Innocent Railway by accident when I lived in nearby Pollock Halls. Taking a late night walk in Holyrood Park with some friends, we suddenly stumbled across a tunnel beneath the ground stretching as far as we could see. The walls were covered in graffiti and water dripped from the ceiling forming puddles that were strangely illuminated by the electric lights in the roof. It all felt very mysterious and unsettling and we walked through the tunnel with some trepidation, speculating about where it might lead us — only to emerge, disappointingly, in a nearby housing estate. In the sober light of day, the tunnel appeared much more prosaic, but I later found out that it is an interesting historical relic, Edinburgh’s first ‘railway’ line, built in 1831 to transport goods from Dalkeith into the city. It was labelled ‘innocent’ because those who built it were suspicious of the newly invented steam engine and conservatively chose to make the railway horse-drawn instead. With hindsight, this was obviously not a very astute decision, and so the Innocent Railway has now been long surpassed by more high speed transport solutions. This section, running between Newington and Craigmillar, still survives as a cycle path, and makes quite a nice walk — especially recommended on dark and eerie nights!