"That's my next job, to find three more sites so I can build all these buildings," Mr. Levinson joked, seated at a conference table inside his sleek white offices on 57th Street on Monday. He was surrounded by renderings and models by Zaha Hadid, Richard Rogers, Rem Koolhaas and the winning architect Norman Foster.

"For us, it was really a blend of what's the right concept for Park Avenue, a place that has not had a new building for almost 50 years, an avenue that is quite possibly the most important commercial boulevard in New York City, quite possibly the United State, and what is the place of a new build down the street from Seagrams and Lever House, two of the greatest buildings ever built," Mr. Levinson explained. "We had to determine for that setting what's the right firm. So really, it's a blend of the concept and the firm we can work with."

Mr. Levinson emphasized that this was not a traditional architecture competition, where he was selecting a design so much as a firm. He acknowledged that Lord Norman Foster had a head start, but as the competition got underway, that choice became harder to make.

"Things we knew early on about the Foster organization, it's a very deep bench with a great deal of knowledge about office buildings," Mr. Levinson said. "There is an emphasis on function, the techtonic aspect, but also an emphasis on form, how it fits into the Park Avenue context and makes an impact."

Foster proposed a set of three floating towers—Mr. Levinson called them separate buildings connected by a central spine—with each higher segment held aloft by dramatic trusses. In the spaces between the office blocks are vast open spaces, some 42-feet high, that will be open to building occupants and occasionally the public.

"We wanted to address the public realm, how does a building fit in to the public realm, the way people approach the building," Mr. Levinson said.

This was true of all the designs, but the way they addressed them were different. Rem Koolhaas conceived of a dramatically torqued building, with retractable walls throughhtout to reveal the spaces or protect them from the elements. Richard Rogers created what Mr. Levinson joked was an "Adirondack park." Like Mr. Foster's plan, there are three discreet office volumes, but here they are held up by a robust orange structure with diagonal cuts to make room for pocket parks, planted with tall pine trees—certainly nothing else like it in New York. Zaha Hadid created a sinuous building that resembles a giant white flower. It has cutouts at the base of the petals, in the towers four corners, which would have been open to the sky.

"Rogers we knew would have an exoskeleton, something very muscular, Zaha would create something real organic, Rem would have some movement and a very cerebral project and Foster would have elegance with an emphasis on the presence of the building," Mr. Levinson said.

It is a challenging commission since all the firms were given the task of peeling back 75 percent of the current boxy building that sits at 425 Park Avenue, then building back up from the base that remained. This was part of a zoning quirk that were Mr. Levinson to demolition the entire building, he would actually be forced to build something smaller than the current building, about 500,000 square feet compared to 650,000.

Mr. Levinson is eagerly awaiting the Midtown East rezoning, which might remove certain impediments to his project, like a better base to the building, but he also admitted that he does not expect to build an even bigger building, even though the new zoning would allow it, up to 24 FAR, compared to the 18 FAR the building currently has (current zoning only allow 15 FAR, but since the building was built before the zoning was revised in 1961, it is bigger than that).

"We are building a bespoke office building," Mr. Levinson explained. "I don't think we need to go much bigger than what we have now. Around Grand Central, bigger might work, but this is the Plaza District, this is a bespoke office building, and I believe this is the right size for us."

Mr. Levinson said he was not joking about finding a place for all these architects in his stable. "We actually do hope to work with all the firms in the future," Mr. Levinson said. No doubt the city's architecture cognoscenti hopes he does.

Bring it up. (dBox/L&L Holdings)

Who needs the Midtown East Rezoning to transform the area when you have intrepid developers and unlikely circumstances? O.K., so both of those are super-rare, so bring on the rezoning,

In the meantime, though, we can occupy ourselves with David Levinson's daring plan to tear down 75 percent of 425 Park Avenue and replace it with a dynamic new tower by Lord Norman Foster. Foster + Partners have emerged victorious from a competition Mr. Levinson's L&L Holdings held over the past few months between some of the world's most high-profile designers. The British Pritzker Prize winner beat out fellow starchitects Rem Koolhaas, Zaha Hadid and Richard Rogers (no Americans, unfortunately).“We are grateful to each of the firms for the thoughtfulness and creativity they demonstrated throughout the process,” Mr. Levinson said in a release. “There is no doubt that each group was fully capable of helping us realize our vision of a 425 Park Avenue tower that redefines the modern office environment while also respecting and enhancing the timeless allure of the Plaza district.”

The project poses an unusual challenge. Because the existing 32-story building was built in 1957, it is larger than current zoning (created in 1961) allows. Were Mr. Levinson to demolish the entire building, he would be forced to replace it with a smaller structure. But his clever real estate attorneys have determined that they could retain the base of the building, building a replacement up from there, and, through some zoning wizardry, maintain the new building at the current one size, 650,000 square feet.

425 Park today.

The new building as currently conceived will reach 687 feet, considerably taller than the 370-foot structure it will be replacing. The design by Foster + Partners is interesting in part because it looks somewhat like a midcentury office tower in the Seagrams/425 Park vein, except that it has been judo-chopped in two spots and is now held up by giant trusses. This not only breaks up the scale of what would likely be a massive building but also creates two terraces, an increasingly popular amenity in office towers. On the street, a rendering shows a vast plaza, providing much-needed open space (even if there is a building overhanging it) in the heart of Midtown.

Should the Midtown East Rezoning be approved, it would allow Mr. Levinson to potentially build a tower 50 percent bigger than what he already can do, but he would have to wait until 2018 to do so, because of a special provision in the rezoning to protect the development of projects at Hudson Yards and the World Trade Center, where millions more square feet of office space is already poised to come online.

Lord Foster is best known for his pioneering work on what became known in the 1970s and '80s, when he began to build serious projects such as the  HSBC headquarters in Hong Kong and London's Stansted airport, as high-tech or high modern architecture. In New York, he has built the new Hearst Building and the Sperrone Westwater Gallery on the Bowery as well as designing 2 World Trade Center, the second tallest building on the site that is indefinitely stalled at the moment.

For those eager to get a look at all of Foster + Partner's designs for 425 Park, as well as the three losing proposals, they will be on display Oct. 18 and 19 as part of the Municipal Art Society's annual MAS Summit, to be held at Jazz at Lincoln Center.

Correction: An earlier version of this post stated the new building would be not much taller than the existing one. In fact, the new building is almost twice as tall. It also credit Lord Foster with designing the Pompidou Centre with Richard Rogers. It was he and Renzo Piano that built the Paris museum. The Observer regrets the errors.

425 Park Avenue, before it needed tearing down. (Eral Soto)

In what sounds like a cross between a party and a design crit from architecture college, L&L Holdings held four marathon sessions last week to explore proposals for replacing the tower it owns at 425 Park Avenue with a new modern office building.

Last year, L&L revealed it planned to tear down the 1950s office block and replace it with something new. A complication in the zoning meant L&L had to keep the bottom 25 percent of the building intact, otherwise the developer would be forced to replace the current building with something smaller. It tapped 11 of the world’s top architects to come up with their own plans, then chose four to present preliminary designs, which took place last week.

These starchitects—Rem Koolhaas, Zaha Hadid, Norman Foster and Richard Rogers (all foreigners, including three Brits!)—each gave two hour presentations at L&L’s West 57th Street offices, according to a source, one in the morning, one in the evening, on Tuesday and Wednesday of last week. This was followed by either lunch or dinner at a different nearby restaurant.

An early model of a possible replacement. (L&L)

The architects themselves were on-hand to make the presentation to L&L principals David Levinson and Robert Lapidus and their deputies. There were joined by a design advisory committee led by Columbia real estate dean Vishaan Chakrabarti, CBRE CEO and REBNY chair Mary Ann Tighe, Municipal Art Society president Vin Cipolla and former Landmarks Commission chair and current Hunter College president Jennifer Raab.

According to our source, the designers each presented two different proposals, one in which the 25 percent provision was considered and another where the building could be torn down and replaced at the current floor-area-ratio with no restrictions, at an FAR of 18. There was no discussion of the recently announced Midtown East rezoning, which could allow buildings of exceptional quality to rise to a 24 FAR—50 percent bigger than the current zoning, a bonus that seems to tantalizing to pass up—because the plan had not yet been revealed.

The architects could always come up with such schemes at a later date, as the project is not expected to commence until 2015, when the tenants clear out all at once. Normally, this would present a major challenge for a landlord to re-tenant the building, but L&L has decided to use it to its advantage in replacing the aging structure instead.

Details of the different designs were not available, but they were said to be impressive. "They put a tremendous amount of time and thought into their presentations," the source said. "They were extremely detailed and highly creative in their solutions to the site’s challenges."

The details were confirmed by an L&L representative who declined to comment further. The designs are due to be unveiled sometime in the coming weeks, with a finalist to be announced by the end of the year.

Steve Roth's Vornado, in the hunt for an anchor tenant, is the developer for the tower, which would sit across the street from the Renzo Piano-designed New York Times building.

Pelli Clarke Pelli designed the Bloomberg tower on Lexington Avenue for Vornado; Mr. Rogers' firm designed the planned Tower 3 at the World Trade Center; and KPF was signed on for JPMorgan Chase's now-scuttled new investment banking headquarters (with a notable goiter for trading floors) downtown.

Images below.

Rogers Strik Harbour + Partners:

Kohn Pedersen Fox:

Pelli Clarke Pelli:

The design by Mr. Rogers, along with two other designs (New York-based SHoP was said to be working on a design for the tower at one point), is expected to be presented at today's Port Authority board meeting.

Mr. Rogers, whose works include the planned Tower 3 at the World Trade Center and the Centre Pompidou in Paris, recently withdrew from a nearby project: the now scuttled Javits Center expansion.

We'll (hopefully) have more after the meeting at 1:30.

The Pritzker Prize-winning Mr. Rogers was brought on for the project by Pataki development chief Charles Gargano in part as a means to draw public support for the project. Mr. Rogers designed, among other projects, Paris’ Centre Pompidou museum with Renzo Piano.

Left with just a renovation (to the tune of at least $800 million) and possibly a modest expansion, the architectural fees grew to a point where the oversight board of the Javits expansion was concerned about costs, according to multiple people familiar with discussions. Last month, the board members were presented with a preliminary yearlong contract of architectural fees of more than $20 million, according to those familiar with the discussions, an amount the board wanted reduced substantially.

Mr. Rogers is not without work in the city—he is the architect for Tower 3 at the World Trade Center, where early construction work has begun.

The New York-based FXFowle, the ESDC spokesman said, is still on the architectural team.

Update: 5:00 p.m.

ESDC spokesman Warner Johnston wrote to say that given the change of scope in the project, "Rogers Stirk Harbour + Partners – in full agreement with the ESDC and its joint venture partners, FXFOWLE ARCHITECTS and A. Epstein and Sons International, Inc – believes that the present objectives are best served by the client working with a local team and has withdrawn from its role as lead designer."

The Paterson administration is trekking down the path of a renovation and modest expansion for Javits, with plans for an additional 50,000 square feet of exposition space and a truck storage area. The budget, at least as of a few weeks ago, was $1.3 billion for the whole ordeal, $300 million or so less than the amount approved for a much larger expansion and renovation under the Pataki administration (which the Spitzer folks later found to have a true cost of more than $3 billion).

The Spitzer administration received a flurry of heavy criticism after it announced this plan for Javits via a January New York Times article, mostly due to the previously unannounced intention to sell some adjacent land. The state backed away from its sale of a parcel to the north (the block between 39^th and 40^th streets), though it is unclear what the Paterson administration intends to do with the block between 33^rd and 34^th Streets, which were also slated to go on the selling block.

These most recent plans, along with the above rendering, were presented to Javits’ governing board this morning (we made the mistake of observing via Webcast, which was without sound).

Another item of note: Despite the state chopping down the amount of new exposition and meeting space by more than 450,000 square feet, the project, by and large a renovation at this point, still has starchitect Richard Rogers signed on to its design team, Empire State Development Corporation spokesman Warner Johnston confirmed.

If that’s not news, the 200-odd media people who turned out, many from national and international news outfits that cover developments like this from a distance, will try to believe really hard that it is. Instead of starchitects Richard Rogers, Sir Norman Foster and Fumihiko Maki, who attended last year’s unveiling of the actual designs, senior staff people from each of the three firms gave updates.

Yet the renderings looked remarkably the same, aside from a few details at street level.

“We feel much too much discussion of these projects being towers, and we can't hide the fact that they are,” Gary Kamemoto, director of Maki and Associates, said. “But what’s probably more important is, how do these very big buildings come down to the ground and create a life to reurbanize this part of lower Manhattan?”

An example from Tower 4, which his firm is designing: a polished black granite wall in the lobby which should reflect the World Trade Center memorial across Greenwich Street (see above). Sir Foster has placed glass elevators on the outer walls of his tower so that passers-by can watch traders going up to their floors (and vice versa). Mr. Rogers is planning a “media wall,” to be designed by an as-yet-unnamed artist, which would flash images and videos inside the office lobby but which would be visible from the street.

Mr. Silverstein has put up more images here.

According to Kresky,

By the way.

--Azi Paybarah