Cody Dock Rolling Bridge
The Cody Dock Rolling Bridge is a moveable pedestrian bridge in London, England at Cody Dock. The bridge is manually rolled using winches to alternate between pedestrian and boat traffic. It crosses a channel that runs from River Lea to a nearby dock. It was designed by Thomas Randall-Page and Tim Lucas, and built by Cake Industries.

The Cody Dock Rolling Bridge is a moveable pedestrian bridge in London, England at Cody Dock. The bridge is manually rolled using winches to alternate between pedestrian and boat traffic. It crosses a channel that runs from River Lea to a nearby dock. It was designed by Thomas Randall-Page and Tim Lucas, and built by Cake Industries.
Check the official site before travelling; hours and prices can change.
More bridges

Tower Bridge
The bridge people mean when they say London Bridge. Walk the high-level walkway for the glass floor.

Millennium Bridge
Foot-only suspension bridge from St Paul's to Tate Modern — the only crossing aligned on St Paul's dome.

Hammersmith Bridge
Currently pedestrian-only, Victorian wrought-iron beauty — best photographed at golden hour.
Source: wiki-list