Former first lady Barbara Bush has died at age 92; tributes pour in
03:01Barbara Bush, matriarch of one of the most powerful political dynasties in American history, died Tuesday at age 92. Bush was married for 73 years to President George H.W. Bush, and was the mother to President George W. Bush. NBC News' Andrea Mitchell takes a look at the life and legacy of the former first lady, known for her wit and emphasis on family.