Six similar plans for the redevelopment of Ground Zero in New York have been unveiled, with none including structures as tall as the twin towers.
The blueprints all feature memorials and proposals to replace the 11 million square feet of office and retail space lost when the World Trade Centre was attacked.
Two of the designs include commercial development on the so-called footprints of the fallen towers, something many victims' relatives oppose.
Officials emphasised the proposals were only starting points for further discussion.
"Nothing is etched in stone, no final decision has been made," said Mr John Whitehead, chairman of the Lower Manhattan Development Corporation.
The blueprints all include a cluster of buildings around open space and a memorial. The highest proposed structure is 85 storeys high, compared to the 110-storey World Trade Centre.
The final design for the tribute will be chosen from an international design competition that would draw on professionals and amateurs alike, he said.
Among the designs submitted, "Memorial Plaza" would feature an 8-acre open space and a free-standing tower at the north-west corner of the site, while "Memorial Triangle" would create several triangular parks and triangular building sites.
"Memorial Park" would have a 6-acre park but would allow commercial development on the footprints.
The six proposals will be narrowed down to three by September and the final choice will be made in December.