Temple of Olympian Zeus
The entirety of the sanctuary was built in a space estimated to be around 250 x 130 meters, enclosed by a low wall with evenly spaced Corinthian columns. Featured in the center was the Temple of Zeus, made of Pentelic marble and measured to be 110.35 x 43.68 meters. Each Corinthian style columns reached the gigantic heights of 17.25 meters with a diameter of 1.7 meters and 20 flutes. The longer side of the temple featured 20 columns each, with 8 on the shorter sides, a style called dipteral octastyle. Originally, the columns were placed in triple rows on the shorter side and double rows on the longer side, resulting in a total of 104. Each column was heavily decorated with marble Corinthian capitals and contained massive gold and ivory statues of Zeus and Hadrian within the inner chamber of the temple. Currently, it only has 15 of its original 104 columns left standing, with a 16th column remains on its side after being blown down by a storm in October of 1852.
Sources:
https://www.ancient.eu/article/815/temple-of-olympian-zeus-athens/
https://www.athensguide.com/temple-of-olympian-zeus/