Watch the video:Marianne Mather, theChicago Tribunephoto editor whodiscovered the new images, and Ted Wachholz, executive director of theEastland Disaster Historical Societydiscuss the events of July 24, 1915.

One hundred years ago this week, the SS Eastland sank in the Chicago River. Nearly 100 newly found photos from theChicago Tribuneoffer a new look at Chicago's deadliest tragedy.

What started out as a day of celebration for more than 2,500 workers of the Western Electric Company turned into the deadliest disaster in Chicago history. On the morning of July 24, as workers and their families gathered aboard the SS Eastland for a trip to Michigan City, Ind., problems with the ship's weight and ballast tanks – which had been emptied before the launch – caused the ship to roll over while it was docked in the Chicago River. As a result, 844 people drowned or were suffocated.

Historical photos and newly discovered video footage show bystanders and officials trying to help save the drowning victims, but 22 families were wiped out entirely.

In this episode of "Chicago Time Machine," which originally aired in August 2013, Geoffrey Baer discusses the events surounding the disaster.

In this "Chicago Tonight video" from February 2015, Phil Ponce talks with Jeff Nichols, who discovered the first-known footage of the Eastland Disaster, and Ted Wachholz, Eastland Disaster Historical Society executive director.

Read more about the Eastland Disaster in "Chicago Stories."

Local celebrations

The Eastland Disaster Historical Society hosts a weekend of events (July 24-26) in honor of the 100th anniversary, including several public ceremonies along the riverwalk (between LaSalle and Clark streets) on Friday at 1:00 pm, and Saturday at 11:00 am and 8:30 pm. Saturday's evening ceremony includes a concert, candle-lighting ceremony and songs from Lookingglass Theatre Company's production of Eastland: A New Musical.Visit the EDHS for more details and ticket information.