For the 2004 Olympics, this park with several stadiums and a pool was revamped by Spanish architect Santiago Calatrava, who built a signature winglike canopy on the main stadium's roof. It hosts major sports events and concerts. There are guided tours for groups (minimum 15 people; per person €3) but independent travellers can wander around to see such features as the wavy, white Wall of Nations display.
Of all the Olympics facilities, this is the only one that is maintained and regularly used. (Unfortunately, spaces such as the pool and tennis centre are open only to registered members, not day visitors.) The rest, scattered around Athens and the southern peninsula, have been largely left to decay, due to a lack of funds for maintenance.