When terror came to London
It's been a week in which one man brought mayhem to Britain's Parliament, fatally stabbing a police officer and mowing down dozens of civilians. Such violent attacks on the symbol and substance of Britain's democracy are rare. We'll hear how this week's attack links to another nearly 40 years ago. And a veteran observer of Northern Ireland pays tribute to another man of violence, but one who turned peacemaker -- Martin McGuinness, who died this week. Photo: An armed police officer is pictured through the Carriage Gates outside the Houses of Parliament in Westminster. Credit: Getty Images