NEW YORK • For two years, the National September 11 Memorial Museum, built at Ground Zero, has presented visitors with a collection that reflects the moments of horror and heroism 15 years ago when terrorists destroyed the World Trade Center.

Now the museum is moving beyond its array of mainly historical items to include for the first time an exhibition of artworks created as a response to the attacks of Sept 11.

The show, Rendering The Unthinkable: Artists Respond To 9/11, opens on Sept 12 in the special exhibits gallery, the inaugural use of that space.

It will include Tumbling Woman, a bronze sculpture by Eric Fischl, a nearly 3,000-piece painting installation by Manju Shandler representing each victim of the attacks and two pieces by Ejay Weiss that mix ash from the site with black acrylic paint and that are meant to evoke the collapse of the towers.

The exhibition is evidence of the museum's interest in complementing its collection of artefacts and archives and an acknowledgment that expanding its scope could add visitors.

"There was always the idea that the museum would have a series of temporary exhibits," said Ms Alice M. Greenwald, the museum's director. "It's a way to bring people back to the museum for a second time and it's a way to bring in people who might not choose to come otherwise."

It is also, she added, a way for the museum to present a new perspective of Sept 11. Although the museum included one commissioned work, by the artist Spencer Finch, when it opened in 2014, it has functioned mainly as a repository for material that documents the attacks on the World Trade Center.

More than 11,000 items, including surveillance footage of the hijackers passing through airports, homemade posters seeking missing people and a fire truck with a burnt-out cab, are displayed in the almost entirely subterranean museum, built where the foundations of the twin towers were carved into the earth. That material, sometimes resembling evidence presented in a criminal trial, can have an overwhelming effect on visitors.

The pieces in the new exhibition are meant to invite a quieter, more contemplative experience, Ms Greenwald said. They show how individual artists reacted to events on that day and include occasional notes of optimism along with reflections of uncertainty and mourning.

Museum employees have long kept track of artworks that referenced Sept 11, Ms Greenwald said. Recently, they selected works by 13 artists that had never been displayed together but had been shown at places such as the Mary Boone Gallery, the New-York Historical Society and the New Orleans Museum of Art.

Curators chose works they believed would resonate together, Ms Greenwald said, adding that some commonalities had emerged. All of the artists in the show are from New York and some had studios in Lower Manhattan at the time of the attacks. Some also had friends or relatives who were killed on Sept 11.

Several artists chose to focus on the sky, depicting dust clouds that filled the air, documents that were carried off by the wind or, in one case, the bodies that plunged from the towers as they burned.

Exhibit 13, created by the three founding members of the Blue Man Group, is a four-minute video showing scraps of singed paper from the towers, including letters, calendar pages and business records in various languages that had been blown across the East River and landed in Brooklyn.

The video, accompanied by sombre music and voices quoting from the documents, is named after a phrase on one of the documents and was intended as a counterpoint to the more pointed tone of contemporary news broadcasts.

"There was a disparity between the aggressive visual landscape of television and a kind of a gentle horror that would dawn on you," said Chris Wink, a Blue Man founder. "Each paper was a different life, a different story."

Fischl's sculpture of a woman with an outstretched arm is on loan to the 9/11 Museum from the Whitney Museum of American Art. When it was first displayed at Rockefeller Center in 2002, the work was deemed too disturbing for some viewers and was removed earlier than scheduled.

The piece, Fischl said this week, was meant to represent those who fell or jumped from the towers in what he called "the clearest illustration of the level of horror" that day, as well as his sense that the country had become less sure-footed after the attacks. Still, the work has an element of hope.

"I extended the arm of the woman because I had this fantasy that if this sculpture is out in public, people will reach out and grab the hand," he said. "Almost in an attempt to connect and also maybe to slow the tumbling down."

NEW YORK TIMES