How do you move history?

Updated 10:21 PM ET, Thu February 9, 2017

Atlanta (CNN)How do you move something that's longer than a football field, tall as a four-story building, weighs almost six tons and, oh yeah, is a national treasure?

With extreme care -- and a lot of expertise.
Later this week, cranes are expected to pluck a colossal painting depicting a Civil War battle from an Atlanta museum that was its home for nearly a century.
The painting, sliced in two and rolled onto enormous steel spools, will be placed on two flatbed trucks for a 12-mile journey to its new home, the Atlanta History Center in the city's Buckhead neighborhood.
Moving an artwork this big is an ambitious engineering endeavor and requires a small army of specialists, from art conservators to crane operators.
And like the aging painting itself, the story behind the artwork, "The Battle of Atlanta," is almost larger than life.

Why was it painted?

02.cyclorama.Troup hurt
Imagine what life was like in the United States before movies and television -- not to mention CGI and other forms of augmented reality. You had to go to the circus or squeeze into a courtroom gallery at a juicy murder trial to find an attraction with a "wow factor."
In the late 19th century, along came paintings called cycloramas -- massive, 360-degree renderings of landscapes, city skylines and war, including this one about the 1864 Battle of Atlanta. The painting was intended as a tribute to a Northern victory.
A rendering for a typical cyclorama.
Cycloramas were about making big bucks, and companies turned them out as fast as they could. Sometimes they would make two copies.
After a year or so in one spot, the paintings -- the IMAX theaters of their day, according to Jackson McQuigg of the history center -- were rolled and moved to another round building to be displayed before new crowds of customers.
Although the heyday of cycloramas in the United States lasted only a few decades, 72 full-size works still exist across the globe, the International Panorama Council told CNN. Not all are on display. China is the most productive country at creating new ones.
Painters, most from Europe, take a break from the Battle of Atlanta project in Milwaukee in 1886.

'The horrors of war'

Really big show

42
Height of painting in feet

49
Height after restoration in feet

359
Circumference in feet

371
Circumference in feet after missing piece is restored

12,000

Estimated weight of painting in pounds, including fiberglass backing

14
Number of panels

7-8
Amount in feet of sky that will be returned to top of painting

6 X 49
Size in feet of vertical section trimmed to fit into the old building; it will be repainted in the new building.

To paint the Atlanta battle, the American Panorama Company in Milwaukee employed a small army of artists -- OK, maybe 20 guys, most from Europe -- to create a work "intended to please Northern audiences" (read Yankees).
The Battle of Atlanta, fought on the afternoon of July 22, 1864, was a decisive moment in the war, and many historians say the fall of the city more than a month later -- during a time the war was grinding on -- helped re-elect President Abraham Lincoln.
As shown in the painting, Rebel troops have broken the Union army's line and federal reinforcements are riding to the rescue. One vignette shows Federal commander Maj. Gen. William T. Sherman and an ambulance carrying the body of one of his favorite subordinates, Maj. Gen. James B. McPherson.
The focal point of the sprawling painting is fierce fighting around a house, with Confederates firing from behind cotton bales. Federal troops and cavalry are rushing toward that point.
"It is the moment when you are on the cusp of Federal victory," said Gordon Jones, senior military historian at the Atlanta History Center.
Charlie Crawford, president of the Georgia Battlefields Association, said the artists did a good job of capturing a moment: "The scene captures the horrors of war: Dead and dying men and horses, broken equipment, dust, dirt (and) smoke."

How did they paint it?

The artists came to Atlanta twice and studied the landscape from towers. They interviewed veterans of the battle and made sure their paint colors matched Georgia's red clay and pine trees.
03.cyclorama.Historical 1886 sketch Troup hurt house
Photographs of 1/10-scale sketches (above) were distributed to the artists, who worked on scaffolds under the direction of the lead artist, filling in grids projected onto Belgian linen.
These guys were really good at their craft. One artist might specialize in horses while another focused on human figures and faces. They made two copies of the Battle of Atlanta painting, although the second no longer exists.
While they got a few things wrong -- "Old Abe," the bald eagle mascot of the 8th Wisconsin Infantry, wasn't really at the battle, and there were no clouds on that muggy day -- veterans and their families were impressed by a work of art that vividly captured the sound and fury of battle.
"This was a way for the veterans to share their combat experience. This is better than going to the battlefield," Jones said. "When you see this, you can say, 'Son this is what I did. This is my experience.'"

Boosting the 3D effect

The painting debuted in Minneapolis in the summer of 1886. After a few moves and a lot of financial distress for owners, the Battle of Atlanta in 1892 ended up in Atlanta -- but not before tweaks were made to appease a Southern audience.
Museum officials decided against building a new revolving stage like this one used at Grant Park location.