The agency responsible for rebuilding the World Trade Center site announced six proposals on Tuesday, all featuring substantial memorials and office buildings — but nothing 110 stories tall. 

"Each plan begins with a memorial acknowledging that as we rebuild, we must remember," John Whitehead, chairman of the Lower Manhattan Development Corp., said at a morning news conference. 

Photo Essay
The WTC Site Proposals

The proposals call for replacing the 11 million square feet of office and retail space lost on Sept. 11 with a cluster of buildings, none of which would rise as high as the vanished twin towers. Each plan calls for the construction of a public transportation hub at the site. They also feature retail and hotel space. 

"The six plans are not final blueprints. Each of the plans represents a package of proposed ideas. These ideas can be mixed and matched and reconstituted based on public input," said Whitehead. 

Talking specifically about a memorial for the site, Whitehead said, "There is no need to rush." He said there would be an international design competition that would draw on professionals and amateurs alike. 

"This is the starting point for dialogue," Matthew Higgins, spokesman for the LMDC, a city-state agency, said earlier. "The next step is to actively engage the public through as many different forums as possible." 

To emphasize the importance of honoring the 2,823 who died, each plan uses the word "memorial" in its title. Four of the plans preserve the "footprints" of the towers for a memorial; two would allow commercial buildings on the footprints, which would enable more intensive development of the site. 

Among the ideas are a proposal dubbed "Memorial Plaza" that would feature an 8-acre open space and a free-standing tower at the northwest corner of the site. "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. 

Groups representing victims' families have demanded that the ground where the towers stood not be used for anything but a memorial. 

"Where Tower 1 and Tower 2 stood is sacred ground," said Joseph Maurer, a retired firefighter whose daughter, Jill Campbell, died in the trade center. "It's the same as Gettysburg or Pearl Harbor." 

The proposals, released by the development corporation and the Port Authority of New York and New Jersey, which owns the land, will be on display for several weeks in Lower Manhattan and on the development corporation's Web site, Whitehead said. 

An expected 5,000 people will discuss the plans at a town hall meeting Saturday at the Jacob Javits Convention Center. 

The development corporation and the Port Authority will narrow the six land-use proposals down to three by September and then down to one by December. 

"The three plans issued in the fall might be a combination of features of the six," said Whitehead. 

The plans were prepared by the architectural firm of Beyer Blinder Belle. Among the firm's better-known projects was the renovation of Grand Central Terminal. 

The six plans are rough drafts — not detailed architectural renderings — and represent the first in a series of steps to redevelop the 16-acre site. Only a few developers, planners and government officials have seen the plans. 

The preliminary plans do not name particular tenants, but there has been speculation that the Museum of the City of New York and the New York City Opera could be located at the site. 

While none of the plans call for housing on the tract itself, they do suggest that damaged office buildings along the periphery could be razed for housing or converted to apartments.