By Katherine Roth, Associated Press

NEW YORK � A building swallowed by flames, sketched in a child's hand. Keys coated in dust and ash. Soot-stained, teary-eyed rescue workers digging through rubble.

These are among the images and objects on display at museums around the country and overseas as the art world marks the anniversary of the Sept. 11 terrorist attacks.

About 150 museums are participating in "Celebrate America's Freedoms: A Day of Remembrance," a project designed to unite communities. Many museums are holding concerts, readings and vigils. Most are offering free admission Wednesday and staying open late, hoping their galleries might serve as a quiet space for reflection.

"Art Museums are places in which human expression communicates across cultures and continents," said Anne d'Harnoncourt, director of the Philadelphia Museum of Art. "We're inviting as many visitors as possible to find solace and inspiration by experiencing the healing power of art."

At the National Museum of American History in Washington, D.C., a scorched piece of the Pentagon's limestone facade and a scrap of twisted steel from the World Trade Center will be displayed, along with other artifacts from the attacks.

Exhibits of photos taken by Joel Meyerowitz at ground zero are on view in 50 cities around the world, including London, Berlin and Jerusalem. In breathtaking detail, they document the scale of the disaster and the emotions of those involved in rescue and recovery.

But nowhere is the impact of Sept. 11 more strongly felt than in New York City, where museums became a much-needed refuge in the aftermath of the attacks.

"As the nation -- and the world -- move from loss to recovery, mankind's greatest artistic achievements continue to serve as symbols of strength and sources of hope," said Philippe de Montebello, director of the Metropolitan Museum of Art, which opened its doors to anyone seeking solace in the weeks following the terrorist assault.

The Met is remembering the tragedy with musical performances and a daylong series of poetry readings. There also will be a display of two chalkboards from Sept. 11 on which firefighters dispatched to the World Trade Center signed out that day. Scrawled on the boards are the names of nine firefighters who were killed.

About a mile from ground zero, the Lower East Side Tenement Museum will close for the morning to hold a memorial service for a man killed in the attacks, Frank Reisman, whose immigrant ancestors are featured in one of the museum's displays. A year ago, the museum shut down its exhibits and became an emergency center, offering water and the use of its telephones and bathrooms to downtown residents.

The New-York Historical Society has various displays examining different aspects of the disaster. One shows a collection of keys found in the rubble of the World Trade Center.

The Museum of the City of New York is extending its exhibit on the city's Arab Americans. It also is showing children's art made in the days and months after the attacks and the Meyerowitz photos of ground zero, and will have lectures, films and readings.

"After 9-11, we found ourselves playing new roles as places for civic engagement," said spokeswoman Sarah Henry. "Museums were a place to connect again, be with people again, affirm the things that are human and that were in a way attacked."

Elsewhere in the country, museums are responding to the "American's Freedoms" theme, proposed at the American Association of Museums conference earlier this year, with moments of silence and candlelight vigils.

San Francisco's Legion of Honor will hold an "Interfaith Night" on the eve of the anniversary. The event features its current exhibition, "Eternal Egypt." Meanwhile, the Scottsdale Museum of Contemporary Art in Arizona will present "Beyond," a space where patrons can talk about what Sept. 11 means to them.

At the Blandon Memorial Art Museum in Fort Dodge, Iowa, residents have contributed hundreds of poems, writings, drawings and photographs for a remembrance collection, said Regina Smith, education director. The contributions will be burned Wednesday evening to symbolize the community releasing its sorrows.

An outdoor art exhibit at the museum has two silos representing the World Trade Center towers and an arch that symbolizes the bridge to healing, Smith said.

The Mercer Museum in Doylestown, Pa., will open "Emblems of Liberty: 19th Century Firemen's Hats," a collection of firefighters' parade hats from the Old Philadelphia Volunteer Fire Department.

"Museums generally are memory places, and I think museums across the country perceived that we had a responsibility to serve in that capacity. ... We certainly wanted to ... provide some thought about the longevity of the values we take for granted as Americans," said curator Cory Amsler.