Kathleen M. Butler was nicknamed the "Godmother of Sydney Harbour Bridge" and also known as the "Bridge Girl". As the first person appointed to Chief Engineer J J C Bradfield's team, as his Confidential Secretary,, she managed the international tendering process and oversaw the development of the technical plans, travelling to London in 1924 to supervise the project in the offices of Dornan's, the company which won the tender. At the time it was built, Sydney Harbour Bridge was the largest arch bridge in the world, with the build expected to take six years to complete. Her unusual role garnered much interest in the press in Australia and Britain.

The Sydney Harbour Bridge is a steel through arch bridge in Sydney, New South Wales, Australia, spanning Sydney Harbour from the central business district (CBD) to the North Shore. The view of the bridge, the harbour, and the nearby Sydney Opera House is widely regarded as an iconic image of Sydney, and of Australia itself. Nicknamed "The Coathanger" because of its arch-based design, the bridge carries rail, vehicular, bicycle and pedestrian traffic.