Isthmus of Perekop
According to Strabo, Asander blocked the isthmus of the Chersonesus (Chersonesus Tauricus, modern Crimea) near Lake Maeotis (the Sea of Azov) with a wall which was 360 stadia long ( 53 kilometres, 35 miles) and had ten towers for every stadium. The wall was probably built because the Georgi of the region engaged in piracy. This isthmus was probably the modern Isthmus of Perekop.