Interactive and multimedia displays, climate-controlled storage and display areas for some of its most delicate treasures, and secure space for permanent and visiting exhibits are just part of a $2.9 million plan for the Bangor Museum and Center for History.

Though the museum and center’s fundraising campaign hasn’t started officially, about 50 of the museum’s core individual and business supporters already have raised $921,000 during the effort’s “whisper” phase.

Now museum officials are reaching out to the broader community for the next phase in which there is an opportunity to raise the needed money in a way that could become part of the museum’s legacy.

The Maine Community Foundation recently notified museum and center officials that the project is the subject of a $1 million challenge grant from an anonymous donor.

To collect that money, museum supporters must match each grant dollar they receive with one they have raised themselves. The $921,000 raised thus far does not count toward the challenge grant.

“The headline should be ‘Bangor museum makes history,'” an exuberant Jean Deighan, the museum’s president, said this week.

“Everybody can do something” to take part, she said.

According to Deighan, the $2.9 million will be used to create a safe and appropriate showcase for artifacts, photographs, documents, textiles and other items that tell the stories of Bangor’s rich history, including the Penobscot Indian Nation, early explorers, the European settlers who followed, and the city’s era of dominance in the shipping and timber industries that helped make it one of the wealthiest cities in the world.

The renovation project will involve all four floors of the crescent-shaped, four-story building that overlooks Merchants Plaza. The Broad Street building was donated to the museum in 2005 by William and Sally Arata of Veazie.

The work is slated to begin at the Circular Block at 25-27 Broad St. in June and be completed by June 2008, Executive Director Terri Garner said Thursday. While the work is under way, the museum will maintain a presence in some other building, likely downtown, Garner said.

The museum store is currently open on the first floor of the Broad Street building. Most of the artifacts are currently stored at various locations around the city. The locations are undisclosed for security reasons.

“It’s going to be great fun. We’re really excited,” Garner said of the project.

The Bangor museum’s collection from the Civil War-era was one of the things that attracted Garner to Maine, she said. Besides directing the museum, Garner is pursuing a doctorate in history at the University of Maine in Orono.

The museum’s collection of some 3,500 artifacts includes a rare replica of the Declaration of Independence, weapons belonging to Civil War heroes from Maine, and business records and correspondence from such notables as Hannibal Hamlin, who served as vice president under Abraham Lincoln, Garner said.

“For a researcher, this collection is invaluable,” Garner said, adding she was “astounded” by the depth and breadth of the museum’s holdings when she came on board in 2005.

The Maine Community Foundation, which has offices in Ellsworth and Portland, holds some 800 charitable funds established by donors for the benefit of communities across Maine. It also helps match charitable-minded residents with nonprofit groups working to improve the lives of Maine residents, whether through the arts, social capital, education, environment or other fields.

No amount of wheedling this week could convince Ellen Pope, the foundation’s vice president for philanthropic services, to divulge the donor’s identity.

“I think it’s safe to say that the donor has a very keen interest in history and that this is a wonderful match,” Pope said in a telephone interview.

“This is a classic example of the foundation knowing someone’s interest and making the connection [between donor and recipient],” Pope said.

“I was surprised at the size of the gift. It’s very large,” she said. “I love the idea that the [challenge grant] will fuel further downtown revitalization in Bangor.”

Deighan agreed, noting that the history museum, combined with the Maine Discovery Museum for children and the University of Maine Museum of Art, would offer downtown some critical mass when it comes to culture.

“I see us as three anchors at the mall,” she said, adding that other elements include the Bangor Public Library, the Bangor Symphony Orchestra, the Robinson Ballet Company and the Penobscot Theatre Company.

“I see us all collaborating in the future,” Deighan said.

The secrecy surrounding the $1 million donor has become a delicious mystery for museum supporters.

“I’m thinking it could be anybody,” Deighan said. “I walk down the street now and I look at people and wonder: Is it you? Is it you?”

“It’s just noble,” Garner said of the grant. “It’s beyond generous.” She added that the funding will allow museum supporters to stick with the ambitious schedule they have set for themselves.

“Of course, the city has been working closely with the museum” to create the new home, said City Manager Edward Barrett. “Obviously, it will bring a lot of people downtown.”

While the building’s exterior is in good shape, Deighan and Garner said the museum board has tapped the Portland firm Winton Scott Architects to redesign the interior, which will be gutted and rebuilt.

The board turned to the award-winning exhibition planning and design firm Krent-Paffett-Carney of Boston to develop ideas for displays, which will cover topics ranging from what Bangor was like before European settlers arrived, to its role in the American Revolution, to the Civil War and through the 20th century.

KPC’s credits include an exhibit about Abraham Lincoln for the National Constitution Center in Philadelphia and a $5 million exhibit titled “Slavery in New York” for the New York Historical Society.

Though the company’s initial asking price was beyond the Bangor museum’s budget, Garner said KPC agreed to reduce its rates “as soon as they saw the collections. They got more and more excited the more they saw.”

Though she did not want to give away all the details, Deighan said the displays will have a definite “wow factor.”

Among the special features planned for Bangor is an orientation theater – a multimedia exhibit designed to show visitors the importance of Bangor’s geographic location throughout history. The Penobscot River will be projected onto the floor, displaying motion and context, according to conceptual plans. An introductory film will be projected onto a curved wall using historic images from the museum’s collection to bring the region’s history to life.

Under the terms of the $1 million gift:

. $750,000 will be applied to the costs of renovation, construction and other direct costs.

. $250,000 will be used to establish an endowment fund for the museum and center at the Maine Development Foundation.

. The match is 1 to 1, which means the museum will receive $1 for each $1 it raises. As donations toward the match come in and are documented, money will be released to the museum in $100,000 increments.

. In-kind gifts count toward the match only if they represent actual project expenses that otherwise would be paid for out of pocket.

. The museum agrees to change its name to the slightly simpler Bangor Museum and History Center.

The fact that the donor did not want his or her name attached to the gift was of significance to Deighan and other museum supporters.

“This person wanted us to be who we are,” she said.

For more information or to donate, call Terri Garner, executive director, at 942-1900.

Bangor Museum and Center for History, 25 Broad St., Bangor. Currently Museum store is open 10 a.m. to 5 p.m. Monday through Friday and noon to 4 p.m. Saturday. Tel: 942-1900.

Thomas A. Hill House, 159 Union St., Bangor. Tours by appointment only. Tel: 942-1900.