The September 11, 2001, terrorist attack on the World Trade Center is the most memorable moment shared by tv viewers during the last 50 years, according to a new study by Sony Electronics and Nielsen.

Tv's top 20 most memorable moments:

1. September 11 attacks 2001

2.  Hurricane Ktrina--the levees break 2005

3.  OJ Simpson murder verdict 1995

4.  Challenger space shuttle disaster 1986

5.   Death of Osama bin Laden 2011

6.  OJ Simpson high-speed car chase 1994

7.  Earthquake/tsunami in Japan 2011

8.  Columbine school shooting 1999

9.  BP oil spill in the Gulf of Mexico 2010

10.  Funeral of Princess Diana 1997

11.  Death of Whitney Houston 2012

12.  Capture and execution of Saddam Hussein 2006

13.  Barack Obama acceptance speech 2008

14.  Prince William, Kate Middleton wedding 2011

15.  Assassination of John F. Kennedy 1963

16.  Oklahoma City bombing

17.  Bush/Gore election results 2000

18.  Los Angeles riots/Rodney King beating 1992

19.  Casey Anthony murder trial verdict 2011

20.  Funeral of John F. Kennedy 1963

What's your Most Memorable moment on TV?