The Athens Olympic Aquatic Centre is a complex at the Athens Olympic Sports Complex, consisting of two outdoor pools and one indoor pool, that was built for the 1991 Mediterranean Games. It was refurbished and expanded for the 2004 Summer Olympics. The larger of the outdoor pools, which seats 11,500 spectators, hosted swimming and water polo events. The smaller pool, which hosted synchronized swimming, sat 5,300 fans. The indoor pool, which hosted the diving events, sat 6,200 observers. It is used for swimming, too. In 2022 the two outdoor pools remain wide open to the sky.