At the beginning of Beçin village, about 6km south of Milas on the road to Ören, a steep signposted road climbs to Beçin Castle. Originally a Byzantine fortress, it was remodelled by the short-lived Menteşe beylik (principality) in the 14th century. The castle, crowning a 210m-high rocky outcropping, offers great views of Milas below from its walls.
The ruins of more Menteşe-era structures can be seen across the valley and up another hill, including the Kızılhan (Red Caravanserai), Bey Konağı (Bey’s Residence), Orhan Mosque, the Büyük Haman (Great Bathhouse) and the wonderfully restored Ahmet Gazi Madrasah. You can borrow an English-language guidebook from the ticket booth. Half-hourly dolmuşes run between Milas and Beçin village (₺3).