Clock Tower of Sarajevo, Ottoman clock tower next to Gazi Husrev-beg Mosque in Stari Grad, Bosnia and Herzegovina

The Sarajevo Clock Tower is a 30-metre stone tower beside the Gazi Husrev-beg Mosque in Stari Grad, the tallest of Bosnia and Herzegovina's 21 clock towers. Its four faces carry gilt hands and numerals, and inside 76 wooden steps arranged in a square rise to the mechanism.

Gazi Husrev-beg, an Ottoman governor and one of Bosnia's greatest endowments founders, built the tower; its earliest written record is Evliya Çelebi's 17th-century account. It was rebuilt after Prince Eugene of Savoy's 1697 fire and again in 1762. In 1874 two Sarajevo merchants brought a Gillett & Bland clock from London, and the old Turkish mechanism went to the Vratnik mosque.

The clock shows lunar time, with 12 o'clock at sunset, the Maghrib prayer. During Ramadan, when the tower strikes 24 hours, it signals iftar: lamps are lit on the Gazi Husrev-beg Mosque and a cannon fires from Bijela tabija. The old Turkish clock was moved to the Vratnička Mosque in Vratnik.

The tower stands beside the Gazi Husrev-beg Mosque in Sarajevo's Stari Grad, 30 metres tall and visible from the mosque courtyard. Its 76 wooden steps are arranged in a square spiral and are narrow and steep, so climbing is not for everyone. The clock faces can be seen from the surrounding streets at any hour.

The clock shows lunar time: its hands read 12 at the moment of sunset in Sarajevo, the Maghrib prayer. A caretaker called the muvakkit climbs 76 wooden steps arranged in a square spiral once a week to reset it. It is thought to be the only clock in Europe keeping lunar time.