Athens lies 5 miles (8 km) from the Bay of Phaleron, an inlet of the Aegean (Aigaíon) Sea where Piraeus (Piraiévs), the port of Athens, is situated, in a mountain-girt arid basin divided north-south by a line of hills. Greater Athens has an area of 165 square miles (427 square km). The Kifisós River, only a trickle in summer, flows through the western half; the Ilisós River, often dry, traverses the eastern half. The surrounding mountains—Párnis, 4,636 feet (1,413 metres); Pentelicus (Pendéli), 3,631 feet; Hymettos (Imittós), 3,365 feet; and Aigáleon, 1,535 feet—add to the impression of barrenness. Yet such considerations are superficial when compared with the fecundity of Athens’s bequests to the world, such as its philosophy, its architecture, its literature, and its political ideals.