Beçin is located 5km South of the Milas District, Muğla Province.
The city has hosted many civilizations however, it was not a prominent city in ancient times until the second half of the 13th century, when it was the capital city of the Menteşeoğulları Sultanate. Menteşeoğulları dominated an area in western-Anatolia, which included Muğla, Balat, Milas, Beçin, Çine, Tavas and Köycegiz.
The site has remains of a fortress and settlement area. Within the fortress lies Kızıl Han, Kara Paşa Han and Emir Courtyard, the Orman Lodge, a Church, a Byzantine Chapel, as well as other archaeological remains. The most prominent structures in the city are the Inner Citadel, the Anonym Tombs numbered 1, 2 and 3, the Big Hamam, Zaviye, the Mültezim House, the Orhan Mosque, Hankah, Ahmet Gazi Madrasa, the Bey Mansion and the Bath, the Domed Fountain, Kızılhan, Seymenlik Zaviye, Menteşe Cemetery, Yelli Külliye and the Kara Paşa Madrasa. Most of these structures date back to the 14th and 15th centuries except the citadel, thought to be 4th Century.
The Ahmet Gazi Madrasa, named after the person who commissioned it, dates from 1375 according to the Arabic inscription above its entrance. The entrance portal, while retaining elements of a traditional Seljuk-era portal, has details that resemble European Gothic architecture. Restoration work has rebuilt large sections of the entrance façade on each side of its portal.
The archaeological site of Beçin has been excavated systemically since 1972. In 2000, a hoard of coins, 60,000 of which are Islamic and 850 European were found. It is not only the largest hoard that has ever been found in Turkey, but also the largest cache of Ottoman coins that has ever been found.
The city (both the fort and the village) was added to the UNESCO tentative list in April 2012.