|Capacity:||Gymnastics: 17,600; Basketball: 18,500-18,989|
The O.A.C.A. Olympic Indoor Hall is used to host sporting events. The facility is a part of O.A.C.A. (Olympic Athletic Center of Athens) and is situated in the Athens suburb of Marousi, Athens, in Greece. The arena was opened in the year 1995. It underwent a major renovation from the year 2002 to 2004, done by architect Santiago Calatrava. The Indoor Hall is owned by the Greek Government and operated by the OAKA S.A. It has been the home for the Greek National Basketball team, the Panathinaikos B.C. and the AEK Athens Basketball Club. One of the notable things about the sports facility is the distinctive A-frame roof supported by four 35 meters tall pillars. It was the largest indoor arena amongst those have been used for the 2004 Olympic Games.