ATLANTA (AP) — As preservationists restore Atlanta’s colossal Cyclorama — a landmark that’s a sort of 19th-century high-tech Civil War history lesson — they also plan to showcase an all-but-forgotten drawing that reveals a little-known fact: There once were plans for another Atlanta Cyclorama.

The Atlanta History Center is restoring the 150,000-square-foot, cylindrical panorama painting showing the 1864 Battle of Atlanta. One of the world’s largest artworks, it was painted by German and Austrian immigrants hired in the 1880s to depict key moments in America’s Civil War.

One of the 19th century immigrant panorama painters, Louis Kindt, nearly destroyed the evidence of the second planned Cyclorama. He threw some of his sketches outside on a rainy night in a fit of rage, said his great-grandson, John Kindt. One drawing showed the Battle of Atlanta from a different perspective; the other, the Battle of Nashville.

There’s no evidence either was turned into one of the giant cycloramas he’d planned.

But Louis Kindt’s daughter retrieved the drawings from the rain. They were discovered years later.

“They wrapped them up in protective paper and passed them on through the family, and they finally wound up under my cousin Joann Kindt’s bed,” John Kindt said.

He’s been working with the history center so the public can see the two early drawings when the giant Battle of Atlanta painting goes on display next year.

Also planned: excerpts from diaries chronicling the struggles of the immigrant painters, who endured sea sickness on the steamship that brought them to New York, floods of their Milwaukee studio and personal struggles.

Their stories haven’t been made public because they’re just now being interpreted from diaries more than a century old.

Michael Kutzer, a painter and historian who speaks German, is working to decipher the minuscule handwriting of artist Friedrich Wilhelm Heine, who supervised the painters, and unlock the history in the diaries.

Heine wrote about making sketches for the painting during visits to Atlanta, where he found bullets on the battlefield along with fortifications built to defend the city.

Since 2008, Kutzer has been transcribing Heine’s writings.

“You must like to decipher lousy handwriting, shortenings and a text without punctuation. You have to know the vocabulary of the 19th century,” Kutzer said.

Heine wrote three lines of text in every quarter-inch of space, said his great-grandson, Tom Heine of Madison, Wisconsin.

“He would get several years in one diary because he was printing so small,” Heine said. “And there were a lot of drawings. Soldiers, landscape drawings — hundreds and hundreds of these drawings.”

Heine passed the time on the steamship by playing the flute and reading, he wrote. He and the other painters later traveled around the U.S., sometimes to research battlefields and other times for fun, his diary shows.

Heine writes about making the panoramas authentic, trying to match the landscape.

“He was out in California for a period of time, and he did a painting of the redwoods,” Tom Heine said. “He just captured the color of the redwoods — it just made you feel like you were there.”

Heine and other painters also met with Civil War soldiers in retirement homes and on battlefields before painting soldiers into the “Battle of Atlanta.”

Creating authentic scenes of soldiers was paramount because after the Civil War, “all these veterans would go to these cycloramas and point out where they were on the battlefield to their families,” Kindt said.

With sketches from Georgia in hand, the painters returned to Milwaukee to create the “Battle of Atlanta” at the American Panorama Co., an octagon-shaped building near the Milwaukee River.

The new Atlanta exhibit will include artifacts from what historians call the golden age of cycloramas, a popular form of entertainment in the late 1800s. Painters in Milwaukee and other cities produced massive panoramic paintings often displayed in specially-built round buildings, where spectators paid a fee to view the 360-degree scene.

“Chicago and Milwaukee were the big centers of cyclorama production,” said Gordon Jones, a military historian and curator at the Atlanta History Center. “It was this whole entertainment, art form and spectacle that reached its zenith in this time period.”