File:Temple of Poseidon - Ancient white marbles2.jpg

English: The sacred promontory of Sounio, as Homer called it in his Odyssey, is situated on the SE edge of the peninsula of Attica, 67 km from Athens. On the highest point of this isolated cape, at the height of 70m from sea level, are the ruins of the Temple of Poseidon; the "Cavo Kolones", as sailors call them.

The temple of Poseidon was constructed in c.440 B.C., over the ruins of a temple dating from the Archaic Period. It is perched above the sea at a height of almost 60m. The design of the temple is a typical hexastyle i.e it had a front portico with 6 columns. Only some columns of the Sounion temple stand today, but intact it would have closely resembled the contemporary Temple of Hephaestus on the Acropolis, which may have been designed by the same architect.

In dividing heaven, the watery realm and the subterranean land of the dead, the Olympians agreed that the earth itself would be ruled jointly, with Zeus as king. This led to a number of territorial disputes amongst the gods. Poseidon vied with Athena to be patron deity of Athens. The god demonstrated his power and benevolence by striking the Acropolis with his three-pronged spear, which caused a spring of salt water to emerge.