Kastamonu

Is the focus of a Külliyesi - religious complex - built in the 1440s.

Was built in 1506, and restored in later centuries.

Local history exhibition.

Mir Liva Sadık Pasha was a military commander and built this 22-room mansion in the 1880s to house his harem. Since 1997 it's been an ethnographic museum, depicting town life and handicrafts in the 19th / 20th centuries, and items from Mahmut Bey Mosque (below). Some visitors are disappointed that they don't get an immersive display of the arts of the harem.

Small museum displaying archaeological finds from the area.

Or citadel perches on an outcrop, reached by a 20 min hike up the old town alleys. Built by the Byzantines in the 10th century, this is the "castra" that gives Kastamonu its name. In later centuries it was captured and repaired by the Seljuks, the Candars and finally the Ottomans. The outer walls have disappeared and the inner walls were damaged by earthquakes but partly restored in modern times. You're free to explore it 24 hours.

Large collection of hats, but no signage or explanation even in Turkish.