The Hadum Mosque is Gjakova's most significant historic monument, built in the last years of the 16th century (1594–95) and funded by Hadum Suleiman Effendi, a senior Ottoman official whose name the mosque still carries. It is a single-dome mosque in the classical Ottoman style, with an elegant portico and a fountain courtyard.
The mosque survived the 1999 war largely intact, which makes it the most authentic surviving link to the pre-war city. It is still in regular use. Non-Muslim visitors are generally welcome outside prayer times — dress modestly and remove shoes before entering. The interior is simple and well-proportioned, with painted geometric patterns on the dome.