The plain of Argos is roughly triangular in shape. The base lies along the sea coast from Lerna to Nauplia and the apex is at Mycenae, which thus overlooks the Argive plain as Deceleia overlooks the Attic. The traveller, who, like Pausanias, approaches Argolis from the northeast by way of Corinth and Nemea and sees, as he emerges from the Tretos defile, the Argive plain opening before him to the southeast, will notice among the foothills to his left a rather inconspicuous, but isolated hill standing out between two steep and rocky conical peaks. This is the citadel of Mycenae. It owes its strength to its natural position, which is easily defensible, and it has an ample supply of fresh water from the spring Perseia running into an underground cistern reached by a secret passage. There were also three wells within the walls and at least one rain-water cistern. No enemy can hope to approach its walls in any force without being observed, and its distance from the coast precludes any danger of surprise from the sea. As a seat of power it is admirably placed. It dominates the Argive plain and it controls the routes that lead northeast to Corinth and the rich districts easily accessible thence, the fertile littoral of Achaia or the Boeotian coast with the central Greek plain behind. The site was thus naturally inhabited early in the Bronze Age, probably from the very beginning of that age on the Mainland of Greece about 2800 B.C., and round it on the outlying hills were neighbouring settlements so that the district even then must have been fairly well populated.