The Sydney Opera House is a symbol of Australia. It is recognized as one of the Seven Wonders of the 20th Century and is also a landmark in Sydney. Its white exterior, a shell-like sculpture built on the harbour, like scattered petals floating in the air, have for many years left observers in amazement. It houses a concert hall, a music theatre, a performance theatre, a children's theatre and a photography studio. Auctions, concerts and other events are held every month or even every week.