Mahmut Bey Mosque
Kasaba was once an important settlement in Kastamonu Province. Now it is a small village about 18 kilometres (11 mi) to Kastamonu. But the historical mosque of the village at 41°28′48″N 33°41′17″E / 41.48000°N 33.68806°E is an important cultural building of the province.
It was commissioned by Mahmut Bey, a member of Candarid house in 1366. The mosque is unique in its building style for no cement is used in the construction (except for the mihrab). The roof too was constructed without using any metal element. (In fact it is also known as Çivisiz camii meaning "mosque without nail") The plan of the mosque is rectengular. It is one of the first wood columned and wood roofed mosques in Anatolia. The exterior of mosque was constructed by hewn stone. Ceiling of the building stands on four pillars. Inside of the mosque all the wood surfaces decorated with plant-dye ornaments called kalem işi (literally "pencil work"). The portal of the mosque which was a masterpiece of art however is now kept in the Kastamonu Museum. A replica of the original portal has been mounted in its place.