Come September 11, America will once again mark the anniversary of the worst terror attacks on its soil 16 years ago. Nearly 3-thousand people were killed in New York City, Pennsylvania and at the Pentagon when hijacked commercial airliners were slammed into all three locations in attacks planned and carried out by al-Qaeda.
The memorial this year will be held at Ground Zero with four moments of silence to observe the times when each plane hit and each tower fell. Osama bin Laden, the leader of Al-Qaeda, was killed by US forces in Pakistan in 2011.