Today in history: On May 25, 2020, George Floyd, a Black man, was killed when a white Minneapolis police officer pressed his knee on Floyd’s neck for 9 1/2 minutes while Floyd was handcuffed and pleading that he couldn’t breathe; Floyd’s death, captured on video by a bystander, would lead to worldwide protests, some of which turned violent, and a reexamination of racism and policing in the U.S. Also on this date: In 1787, the Constitutional Convention began at the Pennsylvania State House (