Hijackers crashed United Airlines Flight 175 into the South Tower of the World Trade Center at 9: 03 a. m. ET on Sept. 11, 2001. The second moment of silence is one of seven to commemorate the events 25 years ago that changed the U. S. forever.
Watch: Second moment of silence in NYC at 9:03 a.m. when hijackers rammed plane into WTC South Tower
