CHICAGO -- Film clips have surfaced of a 1915 disaster that left 844 people dead when a ship headed to a company picnic capsized in the Chicago River.

The first-known footage of the Eastland disaster was spotted by Jeff Nichols, a doctoral student at the University of Illinois at Chicago who was looking through seemingly unrelated material on World War I.

Nichols said he found the clips in Dutch newsreels. Title cards describing what happened precede them.

"It's as easily recognizable to someone who cares about Chicago history as the Titanic, so I knew what I had right away," Nichols, who has lived in Chicago for 20 years, told the Chicago Tribune. "I knew folks would go, 'Wow,' even if they had seen the clip before."

The SS Eastland, which was carrying 2,500 people, turned onto its side in the Chicago River in July 1915. It was one of five boats chartered that day to take Western Electric workers and their families and friends across Lake Michigan to a park in Michigan City, Indiana.

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The ship was top-heavy with several lifeboats and rafts, and a crowd gathered on the port side to watch other boats made the Eastland even more unbalanced. It rolled over, sending people and debris flying and trapping passengers in the lower decks, where they drowned.

One 55-second clip shows first-responders and volunteers walking on the boat, and a second 30-second clip shows workers trying to right the ship at least a week later.

Frank Roumen, a collections manager with EYE Film Instituut Nederland, confirmed in an email sent to The Associated Press that the footage is in the institute's archives.

Nichols posted links to the clips on the Facebook page of the Eastland Disaster Historical Society, which later put them on its website.

"It completely defeats the purpose to hoard the thing," Nichols said. "It's something that should be shared, and it's easily shared with lots of folks."

Ted Wachholz, the historical society's chief historian, said photos of the disaster showed movie cameras on tripods, leading him to believe footage existed somewhere.

Wachholz told CBS Chicago: "It had already finished boarding over 2,500 people had been placed on board and in a matter of two to five minutes the ship rolled over, while still tied to the wharf along the Chicago River and 844 people died in a manner of a few minutes...even today I still really can't fathom what it would been like to experience even one small part of it."

Criminal courts never found anyone accountable for the disaster, Wachholz told The Associated Press. But the Eastland was top-heavy in its design, he said, with modifications making it worse over the 12 years it sailed.

The ballast had also been emptied the morning of the disaster, making it even more susceptible to tipping. But a better-designed boat would not have rolled over under the same conditions.

"It just wasn't stable," Wachholz said.

Nichols said that after his initial discovery, he found a copy of one of the clips in another museum, and he guessed that other copies could be out there.

"These (lost) films are discovered where you'd least expect them, so it's not a surprise that it was in the Netherlands," he said. "If it were close at hand, then it would have been discovered a long time ago."

The last known survivor of the Eastland disaster, 102-year-old Marion Eichholz, died in November.