The Pier Head and canal link in Liverpool city centre has won the 2010 RIBA CABE Public Space Award.
The prize was presented on Saturday and jointly awarded by the Royal Institute of British Architects and the Commission for Architecture and the Built Environment.
The project was designed by AECOM's design and planning practice and commissioned by Liverpool City Council and British Waterways.
Covering a gross internal area 270,000 sq ft and completed in June last year, the project connects Leeds Liverpool canal with the Liverpool South Docks.
Sarah Gaventa, CABE's director of public space, was one of the judges and praised the way the scheme complemented its surroundings on a World Heritage site. She said: "This is placemaking at its best."
The other shortlisted schemes were the 7 July Memorial in Hyde Park and Regent's Place Pavilion, two London schemes by Carmody Groarke.