Cape Sounion is the southern tip of Attica, where the mainland ends. The Temple of Poseidon stands on the edge of a cliff about sixty metres above the sea, and from it you can see the Saronic islands and, on a clear day, a long way across the Aegean.

Ships coming up from the south saw this temple first. That was the point of putting it here.

The sanctuary

People were worshipping on this rock long before the temple was built. There is evidence of sanctuaries from around the eleventh century BC, and finds from the wider area go back much further.

Four marble kouroi — large standing statues of young men — were made around 590–580 BC and set up here. They were smashed, most probably by the Persians in 480 BC, and buried in the sanctuary. Two of them are now in the National Archaeological Museum in Athens, together with the architectural pieces from the site.

The Persians destroyed an earlier temple of Poseidon at the same time.

The temple

What stands today was built between about 444 and 440 BC, in the same period as the Parthenon. It is Doric, made of local marble, and it sits on a platform 31 by 13.5 metres at the highest point of the cape.

Sixteen of its columns are still upright, together with two pillars of the porch. On the right-hand one, as you walk in, is the carved signature of Lord Byron, who came here in 1810. He was following a habit that visitors had been practising since Roman times, and the surrounding stone carries many other names.

The second temple and the fortress

Lower down, on a separate terrace, stood the Temple of Athena Sounias. Its plan was unusual enough that the Roman architect Vitruvius wrote about it: instead of columns on all four sides, it had them on two only, the south and the east.

For centuries the two temples were confused. Pausanias, writing in the second century AD, described the temple on the cliff as Athena's. The mistake was only corrected in the early twentieth century, by excavation.

Sounion was also a fortress. In 412 BC, during the Peloponnesian War, the Athenians walled the whole headland to protect the grain ships that had to round this cape to reach Athens. Parts of those walls and towers survive, and they were repaired again in the third century BC.

King Aegeus

The cape carries one of the best-known Athenian legends. Theseus sailed to Crete to kill the Minotaur and promised his father Aegeus that he would raise white sails on the return if he survived. He forgot. Aegeus, watching from the cliff, saw black sails, believed his son was dead, and threw himself into the sea — which has been called the Aegean ever since.