On October 20, 2013 the iconic Sydney Opera House celebrated 40 years since it was officially opened by Queen Elizabeth II in 1973. Designed by Danish architect, Jorn Utzon, the famous landmark is the busiest performance centre in the world with over 1500 performances per year and serves as home to Opera Australia, The Australian Ballet, the Sydney Theatre Company and the Sydney Symphony Orchestra. Utzon famously quit the project following delays and cost blow-outs, but the building was completed, ten years late and fourteen times over budget, without any mention of the architect. Thirty years later, Jorn Utzon was awarded the Pritzker Prize and the Opera House was declared ‘one of the great iconic buildings of the 20th century’. In 2007 it was declared a UNESCO World Heritage Site.