Millennium Footbridge, River Thames, London

Briefly in London in April (25), stayed at Club Quarters St. Paul, had a few hours and explored the spectacular pedestrian-only footbridge, originally dubbed Wobbly Bridge because it was unstable as designed and constructed ! Open in June, 200, shut down after 3 days, took 2 more years to repair.

The bridge's movements were caused by a positive feedback phenomenon known as Synchronous Lateral Excitation, in which the natural sway of people walking caused small sideways oscillations, which in turn caused people to sway in step, increasing the amplitude of the oscillations.

The bridge alignment is such that a clear view of St. Paul's Cathedral south facade is presented from across the river.