The Apadana Palace or the Palace of the Darius and Xerxes is the oldest and, in terms of, the most glorious building of Persepolis. The construction of this palace began on the orders of Darius the Great about 515 BC. It lasted for 30 years, and it ended at the time of Xerxes government. The gathering of the guests of the world's largest empire needed a grand and magnificent hall, and for this reason, Darius founded the Apadana Palace. Apadana in terms of art, history, politics, and architecture is the greatest palace of Persepolis and is the first Iranian building that used stone on the structure.