Kasaba Mahmutbey Mosque Mahmutbey Mosque, located in the village of Kasaba, situated 18 miles (11 kilometers) to the east of Kastamonu, is a significant cultural site in the Kastamonu Province. While the village is small today, it was once an important settlement in the history of the region. Mahmutbey Mosque, commissioned by Mahmut Bey, a member of the Candarid house, in 1366, is a unique structure in that it was built entirely without the use of cement (with the exception of the mihrab) and without any metal elements in its roof. It is referred to as a "mosque without nail" or "Çivisiz camii" in Turkish. The mosque is rectangular in shape and is one of the first wood-columned and wood-roofed mosques in Anatolia. The exterior of the building is made of hewn stone, while the interior features four pillars supporting the wooden ceiling, which is adorned with plant-dyed ornaments known as "kalem işi." The mosque's portal was a masterpiece of art, but is now housed in the Kastamonu Ethnography Museum, with a replica mounted in its place. Mahmutbey Mosque was added to UNESCO's tentative list of World Heritage Sites in the cultural category on April 15, 2014.