A few years ago, Alabama Media Group moved its photo archives into one place. Nearly 100 years of negatives from The Birmingham News, The Huntsville Times and Mobile's Press-Register were brought to the building that housed the presses in Mobile.

It was a reminder, said Michelle Holmes, vice president of content, of what they had. The newspapers started using more from the archives.

"And we kept going back to say, 'oh my gosh, oh my gosh, oh my gosh, look what is in here,'" she said. "And that really helped us understand that it's not those iconic couple of hundred pictures that are meaningful, but it's really what's hidden inside."

On Wednesday, AMG announced efforts to bring millions of images, most never before published, out of hiding. The news organization has donated more than 3 million images to Alabama Department of Archives and History.

"It's a unique visual record of our state spanning more than seven decades in the 20th century," said Steve Murray, the director of the department.

Given the spread across time, geography and the diversity of topics, it doesn't matter what areas people are interested in, he said, they'll find something in the archives.

The collection itself is an unusual one, Murray said. It holds the major political, economic and social stories of the last century from the official papers of record. Extra value comes from the unpublished images, Murray said, that look into people's everyday lives.

The department will soon start work to share these legacy images in a digital way. It's a different challenge than the one posed by born-digital content, which zooms by so fast but often isn't captured or preserved. As more of the world gets documented, he said, less of what's documented is getting preserved.

"Archives of every size at the federal, state and local level are dealing with how to preserve born-digital content," Murray said. "We should not assume that all of these digital image that we see all around us are going to be with us forever."

The department plans to spend the first half of 2017 digitizing the images. Once that's complete, it will present a searchable database to the public. The archives, still in Mobile, will be moved to Montgomery thanks to a state transport company that's donated the cost of moving them.

The archive donation isn't an effort to get rid of something that's a burden, Holmes said, though some of the negatives have started to deteriorate and AMG doesn't have the resources to digitize the collection. Rather, she said, the agreement with the department is an opportunity to partner with community in a way that benefits everyone.

Alabama Media Group will continue using the archives. It's made good use of them before, including working with a University of Alabama class to find stories hidden in the negatives. It also created an ongoing series with images and stories from the collection.

It took awhile for them to understand the scope of what they had in storage in that building in Mobile, Holmes said. Now that they get it, they're hoping the public will, too, with the opportunity to dig through Alabama's history as captured by Alabama's journalists.

Correction: A previous version of this story incorrectly used the word enormity. The photo archives aren't "a grave crime or sin," or "bad or morally wrong." There's just a lot of them. It has been corrected. We apologize for the error.