The temple is located about 500 m (1640 feet) south-east of the Acropolis, and about 700 m (2,300 feet) south of the center of Athens, Syntagma Square. Its foundations were laid on the site of an ancient outdoor sanctuary dedicated to Zeus. An earlier temple had stood there, constructed by the tyrant Pisistratus around 550 BC. The building was demolished after the death of Peisistratos and the construction of a colossal new Temple of Olympian Zeus was begun around 520 BC by his sons, Hippias and Hipparchos. They sought to surpass two famous contemporary temples, the Heraion of Samos and the Temple of Artemis at Ephesus, which was one of the Seven Wonders of the Ancient World. Designed by the architects Antistates, Callaeschrus, Antimachides and Porinus, the Temple of Olympian Zeus was intended to be built of local limestone in the Doric style on a colossal platform measuring 41 m (134.5 feet) by 108 m (353.5 feet). It was to be flanked by a double colonnade of eight columns across the front and back and twenty-one on the flanks, surrounding the cella.