WATCH LIVE: 9/11 Commemoration Ceremony from World Trade Center Ground Zero in New York City

Tuesday, September 11 marks the 17th anniversary of the landmark terror attack on the United States. In remembrance of the day, The National In September 11 Memorial and Museum will observe the day with a ceremony at ground zero to remember the 2,983 people killed in the attacks at the World Trade Center, the Pentagon and aboard Flight 93 which went down in Shanksville, Pennsylvania.

SOURCE: CBS News