Set into the wall near Edinburgh Castle's esplanade, the Witches Well is easy to miss. Most visitors walk straight past it, eyes on the castle. That, in itself, says something.

The cast iron memorial, mounted here in 1912, marks the spot on Castlehill where more people were executed for witchcraft than anywhere else in Scotland. Over two centuries, more than 4,000 were prosecuted. The majority were women. Many were tortured first.

The well's symbolism repays attention. A snake encircles the head of Hygeia, goddess of health, signifying both wisdom and evil. Foxgloves, associated in Scottish folklore with fairy magic, fill the planting. Healing hands and the evil eye face each other across the ironwork, good and evil in uneasy proximity.

VoiceMap's witchcraft history tour uses the well as its final stop, tracing the full arc from Agnes Sampson's arrest and torture at Holyrood to the burning grounds above. It explains what each symbol means and why, over a century on, calls for a larger memorial have never stopped.