It has all the appearances of an arts boom.

Barry Grove: The Manhattan Theater Club Revamps a Legendary Theater Paul Kellogg: Seeking a New Space for the New York City Opera Glenn Lowry: The Museum of Modern Art's New Home Linda Shelton: Creating a Center for Dance in Lower Manhattan

The Museum of Modern Art opened its new space last week, to widespread media attention, most of it laudatory. Building the new museum cost $425 million, took more than two years and will boost the price of museum admission to $20.

But MoMA is not alone among the city's art institutions in seeking new quarters to meet changing demands of artists and audiences.

• The Dia Arts Foundation opened a large exhibition space in Beacon New York to display its contemporary art.
• Last month, the Rubin Museum of Himalayan art moved into what had been Barney's in Chelsea
• The Brooklyn Museum of Art last spring revealed its revamped museum, complete with a fountain and grand new plaza in front.
• A $75 million Visual and Performing Arts Library is planned for downtown Brooklyn, near the Brooklyn Academy of Music.
• The Joyce Theater will get performance space downtown as part of the plans for rebuilding Lower Manhattan.
• Also in Lower Manhattan, the Signature Theater will open a performing-arts complex of three theaters, a bookstore and a cafĂ©.
• The New York City Opera, which also wanted to move downtown, was rebuffed and is now seeking another home that will enable it to leave its current quarters in Lincoln Center.

But, despite the building boom, the past few years have presented challenges to cultural groups in New York City. Leaders of arts institutions speak, albeit gingerly, about declines in attendance and tightening budgets since September 11, 2001. "Since September 11, 2001, there seems to have been a seismic change in audience patterns," said Paul Kellogg of the New York City Opera. "Subscriptions are down across the country, even the world. Single ticket buyers are not buying ahead and they are attending fewer performances."

At a recent breakfast sponsored by Crain's New York, leaders of four top cultural institutions described their efforts, despite such difficulties, to expand and change for the 21st century.

Barry Grove: The Manhattan Theater Club Revamps a Legendary Theater
Paul Kellogg: Seeking a New Space for the New York City Opera
Glenn Lowry: The Museum of Modern Arts' New Home
Linda Shelton: Creating a Center for Dance in Lower Manhattan