The Newseum, the Rosslyn museum of journalism that is closed while it plans a move to the District, had all the modern -- and expensive -- touches one could want in a public exhibit space: 30-foot ceilings, a domed movie theater, a working television studio and a large private park overlooking Washington's landmarks.

All of which heightens the challenge for Westfield Realty, the owner of the facility, as it tries to find a new tenant for when the Newseum's lease expires in June. Several start-up museums are said to be interested in the site; but it is so big (55,000 square feet, not including the large outdoor park, with 34,000 square feet of office space available immediately above) and was so expensive to build (around $50 million, according to Westfield) that few would-be museums have the money to afford it.

But find a tenant -- a museum, if Arlington County officials get their way -- is what Westfield must do. And the result of the search is significant in that it will help determine what kind of place Rosslyn will be in the years ahead.

"The mixed-use urban village concept is that we can live, work and play in the same place and not need cars as much as we might otherwise, and we can have that in Rosslyn," said Roger Murphy, director of the Arlington Convention & Visitors Service, which is closely following the search for a new tenant. "The Newseum site is an important piece of that."

Of the Arlington neighborhoods along the Metro Orange Line from Rosslyn to Ballston, Rosslyn has long been the most urban, but perhaps the least urbane. It is a neighborhood with tall, glassy office buildings, many with fantastic views of Washington. But unlike the less-dense Clarendon, Courthouse and Ballston neighborhoods down the road, it does not have many restaurants, bars and apartments.

That is partly because of the way Rosslyn was conceived 40 years ago. Urban designers envisioned a community without conventional sidewalks and instead constructed an elaborate system of walkways over streets, forgetting the traditional pedestrian traffic that nurtures street life.

In all respects, that is changing. The walkways are being phased out, replaced with old-fashioned sidewalks. Thousands of apartments and condominiums are under construction or in the planning stages.

And the Newseum site, with the right tenant, could play a significant part in advancing those efforts by giving more people incentive to spend time in central Rosslyn.

The outlook is mixed. Since officials at the Newseum decided to move to the District two years ago, Westfield has been looking for another museum tenant, said partner Timothy Helmig.

But with the economic slump curtailing philanthropy, which is at the heart of museum funding, the firm is increasingly inclined to keep its options open. "We've heard many concepts for a museum on the site, but the sponsors just don't have the financial capability to undertake an operation of this size," Helmig said.

As a result, the firm is considering other possible occupants, such as media firms that use studio audiences, or some other tenant that could use the space for public events.

Westfield could face hurdles there; the property is zoned for museum use, so a zoning change would be necessary for other kinds of tenants. And Arlington County officials have repeatedly said they want another museum to move in.

"We would still like a museum," Helmig said. "But we're approaching the end date of the Newseum's lease and feel like we've pretty nearly exhausted the possibilities of getting another museum in here."

Lois Zambo, an executive vice president of brokerage Julien J. Studley Inc., knows the property well, having represented the Freedom Forum, operator of the Newseum, when it first leased the space. She said it could be challenging to find a tenant for such a specialized property.

"It's such a unique space that it's difficult to even begin to contemplate what kind of tenant would go in there other than a museum," she said. "I just know that maybe once or twice in your career you run across a museum that can afford space like that."

But the very things that make it unique could prove an advantage as well. If a group with enough money wanted to set up a museum or other public display, the Newseum site would be the logical first place to consider, Zambo said.

"It works in reverse, too," she said. "It's one-of-a-kind space, and so if you find the right user, you could make a deal quickly."

Neil Irwin writes about commercial real estate and economic development every week in Washington Business. His e-mail address is irwinn@washpost.com.

The Newseum gave up its digs to move to the District. Now property owners have to figure out how to fill the Rosslyn space.Inside the empty Newseum in Rosslyn, a wall TV flashes the latest news and runs an ad for the 56,000 square feet of space that's up for lease.Timothy Helmig of Westfield Realty says his firm has "nearly exhausted the possibilities of getting another museum" to fill the Newseum space.