St. Louis Emergency Agency volunteers assisted victims of Hurricane Katrina trapped on Highway US 90. (AP/ Ben Sklar)
In this Sept. 11, 2001, file photo, the twin towers of the World Trade Center burn behind the Empire State Building in New York. (AP Photo/Marty Lederhandler, File)
A white Ford Bronco, driven by Al Cowlings and carrying O.J. Simpson, is chased by police cars as it travels on a southern California freeway in Los Angeles in this June 17, 1994, file photo. (AP Photo/Joseph Villarin)
(AURN) -- Nielsen Ratings and Sony have named TV's 20 most impactful television events of the last 50 years. The top five:
1. September 11 terrosrist attacks (2001)
2. Hurricane Katrina (2005)
3. The O.J. Simpson Verdict (1995)
4. The Challenger space shuttle explodes (1986)
5. Death of Osama Bin Laden




