Beneath Edinburgh's City Chambers lies a warren of now hidden alleys where once people lived and worked. When the Royal Exchange (now the City Chambers) was constructed in 1753, the top floors of the existing buildings were torn down and the lower sections were left standing to be used as the foundations. This left a number of dark, mysterious passages largely intact. These underground "closes," originally very narrow walkways with houses on either side, date back centuries. Led by guides dressed up as characters from the past, you can revisit the turbulent and plague-ridden days of the 17th century. Dim lighting and an audio track are intended to add to the experience. But of course in their day, these lanes weren't covered by a massive building. Still, this is a popular attraction so booking in advance is recommended.