Drive along the coastal road, passing the wonderful beaches of Glyfada, Vouliagmeni and Varkiza to the most Southern point of Attica, Cape Sounion, where the white marble pillars of the Temple of Poseidon stand.
On the way, you'll get to see the splendid view of the Saronic Gulf and the little islands offshore. After visiting the Temple of Poseidon, take the time to walk the rocky promontory of Sounion.