- Collapse of the Union Prison (August 13, 1863)
A makeshift Union prison in Kansas City, Missouri collapsed on August 13, 1863, killing four of its prisoners. The prisoners were female relatives and associates of proslavery Missouri bushwhackers, and the victims included the sister of guerrilla William T. "Bloody Bill" Anderson. The outraged bushwhackers, especially "Quantrill's Raiders," used the tragedy as justification for their massacre at Lawrence, Kansas eight days later. General Thomas E. Ewing, who happened to own the building in question, then issued General Order No. 11 to depopulate the surrounding counties and remove the base of support for the bushwhackers. Today, the general site is occupied by the Sprint Center, but a historical marker stands nearby.