Corinth is perhaps the first of all Greek towns that became great and wealthy through commerce. There are only two places which in the earliest times deserve to be noticed as commercial towns, namely, Corinth and Crissa; after the destruction of Crissa, Aegina, though more as a country of sailors, stepped into its place. These last two towns carried on commerce chiefly by sea, while Corinth gave itself up more to traffic by land. Its situation was most favourable for commerce, being distant, on the one hand, twelve stadia from Lechaeon and the Corinthian Gulf, and, on the other, forty stadia[18] from Cenchreae and the Saronic Gulf. The place for the Isthmian games was in the neighbourhood of Corinth, on the Isthmus, which is there forty stadia in breadth. But the most important point at Corinth was Acrocorinthus, a rock which according to Strabo, rose perpendicularly to the height of three and a-half stadia, or 2,100 feet: this statement seems to be based upon actual measurement; at present it is impossible to measure it on account of the jealousy of the Turks. The rock is inaccessible on the side of the country, and below it was situated the city of Corinth, in the form of a trapezium; the town was about five miles in circumference, and one of the largest cities of Greece: Athens was not larger. It was built on hills and in the intervening valleys, and surrounded by a strong wall. Towards the city Acrocorinthus was open, but there was only one gate communicating with it. On the top of it a wall ran round its precipitous sides; and the remains of these walls have even in our days been seen from a distance. It was altogether impregnable, at least in the ancient mode of warfare; it was taken once by famine, and twice by surprise. At present it is no longer so strong, and on one side it can be reached by guns from a neighbouring hill.