Gjirokastra's most interesting sight in no way relates to traditional architecture, but instead to a far more modern kind: this is a giant bunker built deep under the castle for use by the local authorities during the full-scale invasion that communist leader Enver Hoxha was so paranoid about. Built in secret during the 1960s, it has 80 rooms, its existence remained unknown to locals until the 1990s. Personal guided tours run from the tourist information booth on the main square all day.
It's an interesting contrast to Tirana's Bunk'Art: unlike the capital's version, this bunker is virtually empty and feels even more creepy as a result. The rooms have their use displayed on the door and nothing else, though it's interesting to note that the bunker – which could hold up to 300 people – had everything from its own classroom to a law court.