Sydney Opera House is still revealing its secrets as it turns 50

Construction's second stage of Sydney opera house (1963-1976) © David Moore photography - Paolo Tombesi has rewritten an important part of the history of this gem of Australian architecture. Tapping into previously unexplored archives, he found that its distinctive roof - consisting of shells in the form of boat sails - was assembled through a remarkable feat of engineering. The Opera House is as emblematic of Sydney as the Eiffel Tower is of Paris. Masterpieces of 20th-century architecture such as these continue to captivate engineers and enthusiasts alike. The Opera House will turn 50 on 20 October 2023 and a number of commemorative events are planned, including some that will shed light on the building's tumultuous construction process, which lasted 15 years. Our discovery is important because it lets us piece together the Opera House's history using a rigorous approach based on shop drawings that long sat forgotten in the archives. Paolo Tombesi - Tombesi, a professor at EPFL's School of Architecture, Civil and Environmental Engineering (ENAC), is an expert in large monuments and has spent over 20 years studying the Sydney Opera House.