As was typical of Assyrian and Persian palace complexes, Persepolis was built atop a huge limestone platform that served to level off the site and provide a secure foundation for its structures. Surviving ruins provide evidence of characteristically massive palaces built according to the post and lintel, or trabeated, technique. In all of the complex's larger structures, lofty stone columns rising from bell-shaped bases and crowned by ornate double capitals originally supported wooden roof beams. At the time of its destruction, the terrace at Persepolis contained the palaces of Darius, Xerxes, and Artaxerxes III, along with a harem, a labyrinthine treasury, and several ornamental gateways approached by double stairways that converged at the top. Other impressive structures included the great Apadana (audience hall) of Darius and the so-called Hall of One Hundred Columns, or Throne Hall, of Xerxes. The stairway leading to the Apadana is decorated with relief sculpture depicting the parade of Persian nobles and tribute-bearing subject peoples during the sacred New Year's festival.

Pasargadae
Pasargadae, in southwestern Iran about 48 km (30 mi) northeast of Persepolis, was the capital of Cyrus the Great (550-530 BC), founder of the Persian empire. The site supposedly marks the place where Cyrus defeated the Medes and established Persian independence. Archaeologists believe that the coronation of later kings occurred there and that it was the site of both a major imperial treasury and Cyrus's tomb.

Excavations at Pasargadae, begun in 1928, have revealed a fortified citadel with a stone platform that was intended as a foundation for a palace but was instead used as a base for a storehouse, possibly the treasury. A residential palace surrounded by a park and also a columned audience hall have been found as well as a sacred precinct containing three temples. A large stone tower, once called a fire altar, is now thought to have been a storage place for sacred emblems. To the south stands the 12-m-high (40-ft) tomb of Cyrus, built of huge limestone blocks.

Susa
Susa (Shush), in southwestern Iran, was the ancient capital of the Elamites, an administrative center and royal residence under the Achaemenids and the eastern terminus of the Persian Royal Road that ran westward to Lydian Sardis, about 2,575 km (1,600 mi) away. Following the conquests of Alexander the Great, Susa was made a Greek colonial city-state called Seleucia-on-the-Eulaeus; it continued to flourish as a trade center through the Parthian and Sassanian periods, until its capture (AD c.640) by Islamic forces.

Rediscovered in 1850, Susa has been under almost continuous excavation by French archaeologists since 1897. Although occupation levels date back to Neolithic times (c.4000 BC), the principal objects of interest at the site are four large mounds representing the citadel, the palace of Darius I (r. 521-486 BC), and two sections of the ancient city. Significant finds at Susa have included early painted pottery and seals, proto-Elamite writing, an extensive Parthian cemetery, and the famous stele of Hammurabi bearing his law code