London bridges across the river Thames: 5 Millennium bridge

Millennium bridge

Millennium bridge, officially known as the London Millennium footbridge, is a steel suspension bridge for pedestrians, linking Bankside with the City of London

construction of the bridge began in 1998, with the opening on 10 June 2000 and was immediately nicknamed the "wobbly bridge" after participants in a charity walk on behalf of Save the Children to open the bridge felt an unexpected and, for some, uncomfortable swaying motion

after two days of limited access the bridge was closed for almost two years while modifications were made to eliminate the wobble entirely, it was reopened in 2002.

the bridge's movements were caused by a 'positive feedback' phenomenon, known as synchronous lateral excitation, the natural sway motion of people walking caused small sideways oscillations in the bridge, which in turn caused people on the bridge to sway in step, increasing the amplitude of the bridge oscillations and continually reinforcing the effect

an artistic expression of the higher-frequency resonances within the cables of the bridge were explored by Bill Fontana's 'harmonic bridge' exhibition at Tate Modern in mid-2006 which used acoustic transducers placed at strategic locations on the cabling of the Millennium bridge and the signals from those transducers were amplified and dynamically distributed throughout the turbine hall of the Tate (http://www.youtube.com/watch?v=L2KO38Z-2SU)