About 90,000 people crossed London’s new Millennium Bridge on the day it opened in June 2000, with as many as 2,000 on the deck at once, and it swayed so badly it closed days later; subsequent work found that as few as 160 pedestrians could trigger the instability, and the fix was a system of dampers installed on the bridge.
The story most people carry about the “wobbly bridge” is that crowds marching in step shook it, or…
