The motorway connecting the two regional metropolitan centers, İzmir and Manisa, crosses between the two neighboring masses of Mount Sipylus and Mount Yamanlar through the Sabuncubeli Pass, which was much described by ancient travellers and writers and which descends from an altitude of 600 m to sea-level in only a few kilometers. The highest point of the pass corresponds to a point near the boundary between İzmir Province and Manisa Province. To bypass the steep and twisted Sabuncubeli Pass, the -long Sabuncubeli Tunnel was built from 2011 to 2018.