The Sydney Opera House is located in the Sydney Harbour, close to the Sydney Harbour Bridge. Just near the Sydney Opera House are the Royal Botanic Gardens and Circular Quay. It is the second symbol of Australia and probably the most photographed site in the city. The construction of the building began in 1959 and completed in 1973. The Opera House is one of the most spectacular buildings which was designed by Utzon, a Danish architect, after an international competition. The roof structures of the Sydney Opera House are commonly referred to as shells, but are instead precast concrete panels. The Opera houses the following performance venues: the Concert Hall, the Drama Theatre, the Opera Theatre, the Studio, the Playhouse, the Forecourt and the Utzon Room. The Concert Hall contains the Sydney Opera House Grand Organ, which is the largest mechanical tracker action organ in the world. The building houses also cafes, restaurants, a recording studio, bars and retail outlets. In the Opera House are available guided one-hour tours daily and two-hour backstage tour including breakfast.