"So what is this place? Mary King’s Close is an Edinburgh alleyway that constitutes part of the city’s famed underground city. In 1753, after Edinburgh—and particularly crowded closes like these—had suffered from the plague and, in turn, overcrowding, the city built a Royal Exchange building (now the City Chambers) where merchants and traders could sell their wares away from disease and filth. Rather than find a new spot, they decided to erect this building atop the existing streets, thereby entombing closes like Mary King’s forever. Although it's fully underground today, it still sports eight-story tenement buildings, complete with doors, shuttered windows, gutters, and even viewable rooms and former stores. It’s accessible by tour only. Wow. So what's the mood like down there? Mary King’s Close is equal parts enthralling and chilling. We're into it. So tell us a little more about the tour itself. This is an interactive experience. Guides are dressed as former residents; you might find yourself being led around by a 16th-century maid or plague cleaner, a 17th-century poet, or a terrifying plague doctor. As you wander around, you'll learn about the ghost stories and dark history of this infamous alleyway. Anything we should know before planning to join one of the tours? It's essential to book tickets ahead—this is one of Edinburgh’s most popular tourist attractions. Does it meet expectations? Mary King's Close may be a major tourist attraction, but it absolutely lives up to the hype. This is a true Edinburgh must-see. Got it. Is there anyone in particular you think it'd be best for? If you’re a history buff, you have to see this; it’s unlike anywhere else in the world. If you're prone to nightmares, or suffer from severe phasmophobia, stay away." - Freya Herring