Round Tower - Prison

Lankaran, Azerbaijan, Azerbaijan

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The Round Tower, officially called Zindan Fortress or the Round Fortress (Azerbaijani: Zindan qalası / Dairəvi qala), is a circular red-brick defensive tower in Lankaran, Azerbaijan, that was built in the 18th century as part of the larger Lankaran Fortress system and later used as a prison, earning it the name “Zindan” (dungeon, prison).

It was constructed around 1768, possibly under the orders of Nadir Shah, and together with a similar tower nearby (now the Lankaran Lighthouse) served as the southern and northern strongholds guarding the fortress, with both towers connected by a secret underground tunnel that allowed two people to walk freely and which was originally used to move prisoners between sites.

The tower is about 20 meters high, with a diameter of 72 meters and thick bearing walls (up to 2.8 meters at the base), and from 1869 until 1959 it functioned as a prison, at times holding far more inmates than its designed capacity of 140, while the parallel tower was fitted with a lantern and became a lighthouse that is still under the Caspian Shipping Company.