Commissioned to celebrate the Greek victory over Carthage at the Battle of Himera in 480 BC, the Temple of Zeus (the Olympeion) was meant to be one of the largest temples anywhere in the Greek world, roughly 110 by 55 metres, dwarfing every other building in the valley. According to the ancient historian Diodorus Siculus, it was built partly using enslaved Carthaginian prisoners of war, forced labour from the very battle it was meant to commemorate.
It was never finished. The Carthaginians returned to sack Akragas in 406 BC before the roof went on, and centuries of earthquakes and stone-robbing have since reduced the structure to a vast, jumbled field of fallen blocks, one of the eeriest sights in the whole park.
Rather than a conventional colonnade, the temple used giant stone figures called Telamons (or Atlas figures) set into the walls between engaged columns, apparently helping to visually support the entablature above. One was painstakingly reassembled from 26 separate tufa fragments in 1825 by the sculptor Raffaello Politi and now lies near the site; the fragments impressed even Goethe, who took home a painting of one of the figures after visiting. The original carved pieces are displayed in the Archaeological Museum.