The Heart of Midlothian is a quirky mosaic heart on Edinburgh's Royal Mile that marks the spot where a notorious prison once stood. Back in the day, this place was like a medieval horror show, with torture, executions, and all sorts of grim stuff going down. Locals now spit on the heart for good luck or maybe just to show their disdain for the dark history of the place. It's a weird tradition, but hey, it's all part of the charm of this historic spot!