U.S. experiences weekend of gun violence

Philadelphia, Chicago and Washington, D.C., experienced an outbreak of gun violence over the weekend. Those incidents were part of a wave of gun violence in which hundreds of people were killed and injured in the last 72 hours, according to the Gun Violence Archive.

In Philadelphia, police responded to 42 shootings that left four people dead over the weekend. Another 56 people were shot in Chicago, with at least eight victims under 18 years old. The City of Chicago is offering $1 million for tips about illegal guns.  "Our children are worth your giving these people up," Chicago police superintendent David Brown said Monday at a news conference.