Perched precariously atop rocky Mt Harşena, the kale offers magnificent views down the valley. The remnants of the walls date from Pontic times, perhaps around King Mithridates' reign, but a fort stood here from the early Bronze Age. Destroyed and repaired by several empires, it had eight defensive layers descending 300m to the Yeşilırmak River, and a tunnel with 150 steps cut into the mountain.
To reach the castle turn left when you get to the Büyük Ağa Medresesi and follow the road for about 1km to a street on the left marked 'Kale'. It's 1.7km up the mountainside to a car park, then another steep 15-minute climb to the summit. Although the castle is popular with families, travellers of either sex are advised not to go up unaccompanied on foot later in the day.
