The idea of a lower Yarra crossing was old long before the bridge existed. As early as 1888 Victoria's Public Works Department proposed a tunnel under the river, and for decades the only way across near the river mouth was by skiff and then by ferry. Melbourne's western suburbs, heavy with industry, needed a real link to the city and the docks. By the 1960s the argument had been settled in favour of a bridge rather than a tunnel, largely because a bridge could safely carry petrol tankers that a tunnel could not. The Lower Yarra Crossing Authority won its franchise by act of parliament, and construction of a long, high steel box-girder bridge began in 1968. It would be high enough for cargo ships to pass beneath, on their way to the wharves upriver.

Two years into the work, the bridge killed thirty-five of the men building it. Many were on their lunch break in the huts beneath the structure when the span came down and crushed them; others were working on and inside the steelwork as it fell. Eighteen more were injured. The roar, the explosion of dust and gas, the fire that followed, reached across the suburbs. The dead were riggers, boilermakers, painters, ordinary tradesmen who had families waiting for them, and the grief moved a nation. The next morning the Premier announced a Royal Commission; the Prime Minister, John Gorton, sent his deepest sympathy to the families to whom, as he put it, this tragic event had brought such grief. These were not statistics. They were workmates who had shared a smoke an hour before, and most of Melbourne knew someone touched by the loss.

The Royal Commission, reporting in July 1971, laid the failure at the feet of both the structural design and an unusual method of construction. Two half-girders that needed to be joined sat eleven centimetres out of alignment. To force the higher one down, the crew loaded it with ten concrete blocks, each weighing about eight tonnes. The weight caused the span to buckle, a clear warning of structural distress. In trying to remove that buckle by unbolting a section of the steel, the workers created a stress concentration the structure could not bear, and with too little margin of safety built into the original design, it gave way about an hour later. The West Gate was not alone: three other steel box-girder bridges collapsed during construction between 1969 and 1971, prompting Britain to rewrite the rules for building them.

Six twisted fragments of the fallen span sit in a garden at Monash University's engineering faculty, kept deliberately so that engineers will remember the human cost of getting the numbers wrong. Every year since 1970, a commemoration has been held on 15 October. A memorial park opened beside the bridge on the thirty-fourth anniversary in 2004, its sculpture and its roll of names ensuring the dead are not folded quietly into the bridge's success. The disaster reshaped Australian workplace safety: in the decades that followed, unions won statutory health and safety committees, mandatory inspections, and worker representation in safety decisions, reforms credited with saving countless lives on building sites since. The men of the West Gate did not die for nothing, but the price was unbearable, and the memorial insists we never pretend otherwise.

Completed in 1978 after a decade of work, the West Gate now spans more than two and a half kilometres and stands fifty-eight metres above the water, windswept and busy at the heart of one of Australia's most-travelled road corridors. Its great height brought a second, quieter tragedy: for years the bridge was a site of suicides, and the loss of life moved Victoria to act. After a series of deaths and coronial recommendations, a metal safety barrier was installed along the full length of the deck between 2009 and 2011, a measure that has reduced such deaths from the bridge to zero in the years since. In 2025 the West Gate Tunnel opened beneath the river nearby, an alternative crossing for a city that has never stopped needing more ways across the Yarra. If you reach the western suburbs, you can ride the small Westgate Punt foot ferry directly below the span, and look up at the great deck the hard way the river always offered.