The Israeli military reports more than 570 rockets have been fired from Gaza this week. Many of them have been knocked out of the sky by Iron Dome, the defense system that intercepts missiles in a matter of seconds. Tom Foreman takes a closer look at how the Iron Dome works.

In a web exclusive, Anderson discussed the possibility of a ground invasion of Gaza with George Mitchell, who is a former U.S. Special Envoy for Middle East Peace.