Clerkenwell Prison

You are standing near the site of what was once one of London's most notorious institutions, the Clerkenwell House of Detention. In the mid nineteenth century, this place was built on the principles of the separate system, designed to keep prisoners in total isolation from one another. While the prison was demolished in the eighteen nineties, a vast network of subterranean vaults remains tucked away beneath the ground. These eerie, windowless spaces are known to locals as the Clerkenwell Catacombs. They once housed cells and internal corridors, and during the second world war, they served the neighborhood as deep-level air raid shelters.