The old "Derby Gaol" can be found under numbers 50 and 51 Friargate in Derby. It is said to be one of the most haunted spots in the country.
The jail ("gaol" is an old-fashioned variant of the word) was used between 1756 and 1828 and was originally (it's believed) two separate cell blocks - in fact, it's thought the facilities could continue under neighbouring properties, too).
It is now a museum and much of the jail has been restored to its former condition.
Whilst the jail was being worked on, clues were found as to what some of the cells may have been used for in the past. For example, marks on the inside of the door of the debtor's cell refer to money and amounts to be paid. There are gallows outside the entrance - a timely reminder of past events.
As well as guided tours, the owner, Richard Felix, also arranges "lock-ins" on some Friday and Saturday nights. Imagine sleeping where a condemned man may have spent his last night!