On this day, 19th August, 1930, the two halves of the Sydney Harbour Bridge arch were joined.
The arch of the Sydney Harbour Bridge was built in two halves cantilevering from each shore and tying each half back by steel cables that were anchored into U-shaped tunnels excavated into the sandstone rock. Construction of the two halves of the arch began late in 1928, and the two halves were properly joined around 10pm on 19 August 1930.
The Sydney Harbour Bridge is the sixth longest spanning-arch bridge in the world and the tallest steel arch bridge, measuring 134 m (440 ft) from top to water level. It was also the world’s widest long-span bridge, at 48.8 m (160 ft) wide, until construction of the new Port Mann Bridge in Vancouver was completed in 2012.(Wikipedia)
These photographs from the State Library of New South Wales collections, depict the arch joined, with the first of the hangers being hauled up from moored barge below.