"For the last five decades, the Sydney Opera House has been a global spectacle: with its whimsical rooftop sails and prime location on the Sydney Harbour, it has become not only the city's most recognizable symbol, but that of all of Australia. While presiding over the building's October 20, 1973, opening, the late Queen Elizabeth II called it “unique”—and while its architecture certainly remains a standout feature, what makes the structure truly forward-thinking is the degree to which Danish architect Jørn Utzon drafted it with sustainability in mind."