Tron Kirk & South Bridge

The church with the elegant spire ahead is the Tron Kirk, built in the 1630s and named after the "tron," the public weighing beam that once stood nearby — where dishonest merchants were sometimes nailed by the ear as punishment. For generations, locals gathered here to celebrate Hogmanay, the Scottish New Year. Now look at the junction: South Bridge crosses the valley to your right, and here's the surprise — it's a bridge of 19 arches, but you can only see one. The rest are buried beneath the buildings that line it. Inside those hidden arches lie the South Bridge Vaults, chambers that housed workshops, taverns and, later, some of the city's poorest residents in damp, lightless conditions. The vaults were rediscovered in the 1980s and are now among Edinburgh's most popular ghost-tour destinations. This city, you'll notice, has a habit of building on top of itself — layer upon layer of history, quite literally underfoot. Cross the junction and keep heading east down the Royal Mile. A couple of minutes on, look to your left for a narrow house with jettied upper floors overhanging the pavement — that's our next stop.