Emmett Till was from Chicago. Why is this significant

Emmett Till's death started the Chicago Race Riots of 1919.

Explanation:

The summer of 1919 is known as the "Red Summer" because several race riots occurred within this time period. As veterans returned from fighting in WWI, many in the black community believed that having fought in the war would grant them respect and racial equality, however this was not the case. This, along with existing tensions created by overcrowding (an effect of the Great Migration) meant that racial tensions in Chicago were high. After Emmett Till was murdered, his mother had him returned home for an open casket funeral. His funeral, along with the death of another black boy, incited protests that turned into violent riots when police and white bystanders interfered. The Chicago Race Riot of 1919 is particularly famous for having been deadly and incredibly destructive, though it was not the only riot to occur that summer.