Immediately recognisable by its sails glistening over the waters of Sydney Harbour, the UNESCO-listed Sydney Opera House is one of the world’s most photographed buildings. Officially opened in 1973 and celebrating its 50th anniversary on Friday, The House as it’s affectionately known, has wowed generations of audiences with world-class performances inside one of the greatest architectural structures of the 20th century. Former architect and now part-time tour guide Peter Sekules’ appreciation for the Sydney Opera House started as a five-year-old when his parents first took him to see the shiny white sails under construction, inspiring a life-long love of architecture. “I remember this unusual shaped building coming out of the peninsula…because a lot of the buildings and houses I was living in were all squares and rectangles and then there was this very funny shape of a building,” Sekules told Reuters from inside the Sydney Opera House Concert Hall. As part of the 1956 Opera House international design competition, 233 designs were submitted by architects from around the world with Jorn Utzon from Denmark chosen as the winner. Construction began in 1959 with the project meant to take four years to complete, but after Utzon resigned due to a change in government, design differences and a blowout in costs, the structure took 14 years to complete. “When I read some of his inspirations for the Opera House, he said he really wanted to make it a contrast to all the squares and rectangles which I was brought up with and to really make this as a piece of sculpture,” Sekules said. “It was a beautiful philosophy.” Sekules says he tried to instil that philosophy when he decided to start his architectural career working alongside Australian architect Peter Hall, who took over the Opera House project after Utzon resigned. Officially opened by Queen Elizabeth II on 20 October 1973, the Opera House is celebrating its 50th birthday with a fireworks and laser show illuminating the iconic building. According to the Sydney Opera House, more than 10.9 million people visit the building every year. The Sydney Opera House was added to UNESCO’s World Heritage List in 2007.