The stadium
The festivities for the assumption of the organization of the 2004 Olympic Games were soon replaced by the fervent preparation for the timely delivery of the athletic facilities. They examined all usual practices followed in the cities that organized the Games in the past and decided that they would follow the "middle road". Therefore, the existent facilities were used, after significant interventions, but a multitude of new ones were also constructed. The original element compared to the previous Olympiads was that the Games were conducted in stadiums that were constructed in three different historical periods: the ancient stadium of Olympia (5th century BC), the Panathenaic Stadium in Athens (19th century) and the Athens Olympic Sports Complex (OAKA) (20th century).
The heart of the Olympic Games was the Athens Olympic Sports Complex (OAKA) at Marousi, which was aesthetically "improved" by the Spanish architect Santiago Calatrava. One of its most characteristic changes was the new roof, which changed completely the way that the stadium looked. The complex includes the Olympic Stadium, the Olympic Indoor Hall, the Olympic Aquatic Centre, the Olympic Tennis Centre and the Olympic Velodrome. The Olympic Stadium, with a capacity of 72,000 spectators, hosted the opening and closing ceremonies of the Games, the track and field events and the football final. At the Olympic Indoor Hall gymnastics and basketball events were conducted, which were attended by 17,500 and 19,250 spectators respectively. The Olympic Aquatic Centre, where aquatic events, polo, synchronized swimming and diving took place, consists of two outdoors and one indoors swimming pool. Its seat capacity is as follows: the central pool 11,500, the closed pool 6,100 and the pool for synchronized swimming 5,300. The Olympic Tennis Centre consists of the main field (8,600 seats), two fields of 4,300 seats and 13 fields of 200 seats. Finally, at the Olympic Velodrome track cycling was conducted and hosted 5,250 people.
For the other sports (boxing, pentathlon, equestrian evens, rowing, sailing) stadiums were created in various areas of Attica. Furthermore, stadiums were renovated or constructed from scratch in various cities of Greece (Thessaloniki, Patras, Volos, Heraklio), which hosted football matches, providing these cities with modern athletic facilities.
Apart from the athletic facilities there were also the facilities of the Olympic Village, an original settlement that hosted all the athletes and their attendants. It was created on the foothills of Parnitha with total area of 1,240,000m2, able to host 16,000 people.