Tour at The Olympic Area in Maroussi
You can book a tour at the large Olympic Stadium in Maroussi. The tour with a local English speaking guide takes about an hour and there will be an Q & A session at the end. The site contains swimming pools, basketball arena, cycle-racing tracks, a large athletics stadium, football grounds, etc. (The facilities cannot be used during the visit). The closest metro station is Irini, and you can arrange to meet your guide here if wanted.