ISARs - are medieval fortresses. The name came from Tatar Isar – a wall, fortress, Kai — a stone. But they have no relation to the Tatar period of the Crimean history. ISARs were build by Romans and Middle Ages lords to control the territories and trade ways. Fortress near the pass "Devil's ladder" was found by archeologists O. Dombrovsky and L. Firsov. At the top of the Isar-Kai rock they found the bases of 7 towers of the medieval period. Here it is also possible to see the remains of Christian basilica.