37°39′07″N 24°01′34″E / 37.652°N 24.026°E
Cape Sounion (Modern Greek: Aκρωτήριο Σούνιο Akrotírio Soúnio [akroˈtirʝo ˈsuɲo]; Ancient Greek: Ἄκρον Σούνιον Άkron Soúnion, latinized Sunium; Venetian: Capo Colonne "Cape of Columns") is the promontory at the southernmost tip of the Attica peninsula, 8 kilometres (5.0 mi) south of the town of Lavrio (ancient Thoricus), and 69.5 km (43.1 miles) southeast of Athens in the Athens Riviera. It is part of Lavreotiki municipality, East Attica, Greece.
Cape Sounion is noted for its Temple of Poseidon, one of the major monuments of the Golden Age of Athens. Its remains are perched on the headland, surrounded on three sides by the Aegean sea.