In a storefront in Soho, crowds gather at a photo gallery where Sept. 11 never ends. Others are drawn to Grand Central Station, where Mayor Rudy Guiliani still stands larger than life among the heroes of ground zero.
Almost immediately, pictures from the most photographed tragedy in history became a new form of art - part memorial, part tribute - that offers the artist and viewer alike a way to connect and collectively share the experience.
Four months later, two exhibits touring the country are drawing thousands of visitors each day, still searching for a way to remember both victims and survivors of the attacks.
One of these photo exhibits at Manhattan's Prince Street Gallery, "Here is New York," captures the World Trade Center's collapse and its aftermath through the lenses of hundreds of amateur and professional photographers.
The other, "The Faces of Ground Zero," which debuted at New York's Grand Central Station two weeks ago and just arrived at the Boston Public Library, features 9-foot-by-4-foot Polaroids of survivors ranging from firefighters to their widows to janitors.
Shane Regan came to the exhibit while it was in New York wearing the jacket of his father, a New York City firefighter who died in the attack.
"It's a great picture," says Mr. Regan, standing in Grand Central Station, of the portrait of his brother, a US Marine who returned home to search for their dad at ground zero. "He's happy they caught him looking dirty."
Visitors here ranged from foreigners such as Shuji Okamoto of Japan to New Yorker Daranice Miguel, who says she brought her teenage son to see "some real heroes." In addition to Boston and New York, the giant Polaroids will stop in San Francisco and London.
Across the exhibit space dwarfed by Grand Central's high ceilings and chandeliers, dozens of spectators crowd around to listen to the story of firefighter Keith Johnson and his three children, who stand in front of his life-size portrait.
"Everything was chaos," says Mr. Johnson, who is pictured in his uniform, holding an ax. "You had to make a decision in a split second. Some people froze and got killed."
Longtime Life magazine photographer Joe McNally used a Polaroid camera the size of a one-car garage to photograph his faces of ground zero. He worked around the clock for three weeks to snap 300 pictures of subjects he found in the newspaper and others who showed up at his door via word of mouth.
"It was certainly emotionally draining," says Mr. McNally. "But you work so hard, you try not to think about the tragedy too much."
Meanwhile, at the Prince Street home of "Here is New York," images of soot-covered office workers, ash-filled streets, and images of the towers collapsing from every possible angle cover the walls and hang from wires overhead. A TV replays a documentary showing ground zero on the first day.
"It's all here, all over again," says Wayne Landman of Atlanta. "I never pictured it like this. This is much worse. This brought it back much more vividly for me. This touches you."
The exhibit began as just a single photo in this former dress shop's window. As crowds gathered outside, a group of photographers started hanging pictures from friends and amateurs inside.
Each picture at the Prince Street gallery is the same size. There is no description or photographer's name, only an ID number to order copies.
Like visitors to the Berlin Wall after the fall of Communism, visitors can take home a piece of the exhibit by buying copies of any print for $25. Money is donated to victims.
Charles Traub, one of the exhibit's four organizers, says they intended the exhibit to bear a "collective witness" to the attacks, where people could revisit the tragedy on their own terms. But none of them imagined just how many people would stop in.
Within days, lines full of New Yorkers, celebrities, and politicians stretched around the block. Visitors have bought 40,000 photos so far.
"Here is New York" will soon relocate to a space in Times Square. Reproductions of the collection première in Chicago today. Organizers are looking for corporations to sponsor exhibits in another 40 cities - from Minsk, Russia, to São Paulo, Brazil - that want to host reproductions.
Other depictions of the attack are also drawing audiences. At the Sundance Film Festival last month, the premières of five documentaries on Sept. 11 left audience members wiping away tears and singing the 1979 song, "We are Family."
A website where visitors can soon buy images from the "Here is New York" exhibit has received more than a million hits. Mr. Traub says it could become the most viewed photo exhibit in history, outranking the "Family of Man," which drew 12 million people in the 1950s. "Photography is the ultimate testament to the event," he says.