I spent about an hour and a half at Mt. Olympieion-Temple of Zeus. Maybe more. It takes a good 30-45 minutes to walk around the whole area + take pictures + just stop and admire. This place was lowkey magical. PERFECT for a photo shoot. Not only the ancient ruins, but Acropolis is right in the distance adding a perfect background.
Entrance fee to the ruins are only 2 Euro. You can also buy a combined ticket to the Archaeological areas of Athens for 12 Euros. These include: Acropolis, Acropolis Museum, Ancient Agora, Theater of Dionysus, Kerameikos, Temple of Olympian Zeus and Roman Agora. Student reduce pricing is 6 Euro.
There is free entrance for the following groups: Minors under 18, Students of European or Greek Universities, Military, Tour Guides.
Free Entrance for ALL visitors: Sundays November 1-March 31, 1st Sunday of every month, National Holidays, March 6, April 18, May 18, June 5.