Soldiers marching on the Broughton Suspension Bridge in Manchester, England cause it to collapse.
Broughton Suspension Bridge was an iron chain suspension bridge built in 1826 to span the River Irwell between Broughton and Pendleton, now in Salford, Greater Manchester, England. One of Europe's first suspension bridges, it has been attributed to Samuel Brown, though some suggest it was built by Thomas Cheek Hewes, a Manchester millwright and textile machinery manufacturer.On 12 April 1831, the bridge collapsed, reportedly due to mechanical resonance induced by troops marching in step. As a result of the incident, the British Army issued an order that troops should "break step" when crossing a bridge. Though rebuilt and strengthened, the bridge was subsequently propped with temporary piles whenever crowds were expected. In 1924 it was replaced by a Pratt truss footbridge, still in use.