The Temple of Olympian Zeus is the largest in Greece, even surpassing the Parthenon. It was built around the 6th century BC, but took 650 years to complete. Only 15 of the original 104 columns remain. Complete, it would have measured about 96 metres long by 40 metres wide. From a distance, you get a perspective of how impressive the temple must have been.
Entrance to the temple was free with the multi site pass I purchased at The Acropolis.
The Panathenaic or Kallimarmaro Stadium is not too far from the Temple of Olympian Zeus and was built on the old site of the Panathenaic Stadium. It hosted the opening and closing ceremonies of the first modern Olympics in 1896. My multi site pass did not give access to the stadium and I didn’t want to pay to enter, so I viewed the stadium from the outside.