Immediately to the east are the poor remains of a large square enclosure, open to the sky and measuring about 30 meters on a side. Built in the early 5th century, at the command of the oracle of Apollo at Delphi, it was dedicated to Aiakos, a hero of the island of Aegina. By the early 4th century it was used for the storage and distribution of substantial amounts of grain. Aiakos was one of the judges of the underworld and the results of judgments handed down in Athens were displayed on the walls of the building.

Excavations in the Athenian Agora are conducted by the American School of Classical Studies.
Primary funding is provided by the Packard Humanities Institute (PHI).