Cape Sounio, the southernmost point of Attica, is home to the remarkable Temple of Poseidon. This temple, built during the classical period of Athens (444 - 440 BC), stands on the ruins of an earlier structure, perched on a 60-meter cliff. In Greek mythology, Poseidon, the God of the Sea, reigned alongside his wife, Amphitrite. Ships approaching the coast were welcomed by the radiant white Temple of Poseidon, a symbol of maritime prowess. The trident he held was used to catch tuna, offered at the Sanctuary of Poseidon. The intriguing use of geometrical connections in ancient city planning is exemplified by the Temple of Poseidon, forming an isosceles triangle with the Temple of Hephaestus in Theseio and the Temple of Aphaia in Aegina. This showcases the precision and foresight of ancient architects and city planners.