The Olympieion, also known as the Temple of Olympian Zeus, is an ancient temple located in Athens, Greece. It was dedicated to the god Zeus and is one of the largest temples of the ancient world. Construction began in the 6th century BCE but was not completed until the 2nd century CE during the reign of the Roman Emperor Hadrian. The temple originally featured 104 columns, of which 15 remain standing today. The Olympieion was renowned for its grand scale and impressive architecture, showcasing the skill of ancient Greek builders. It served as a significant religious site and a symbol of Athenian power and devotion to the gods.