Drive along the coastal road, passing the wonderful beaches of Glyfada, Vouliagmeni & 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 have a splendid view of the Saronic Gulf and the little islands offshore. After visiting the Temple of Poseidon, you have time to walk at leisure on the rocky promontory of Sounion.