A 282-tonne bridge linking two sides of the 2012 Olympic rowing venue on the Buckinghamshire/Berkshire border has been put in place.
Dorney Lake near Windsor, will host the rowing and kayaking events at its centre, with up to 30,000 visitors a day expected.
The 50m (164ft) structure will remain in place after the games and will be used by up to 6,000 people.
It was lifted into place and replaces a previous bridge that was half its size.
Ivor Lloyd, managing director of Dorney Lake, said it would enable organisers at the site to run Olympic regattas far more easily in terms of boat flow and traffic flow.