In New York, visitors crowd the memorial as the Tribute in Light beams skyward from Ground Zero
Workers prepare to unveil the U.S. flag overlooking the 9/11 Memorial at Ground Zero, the site of the September 11, 2001 attacks, in New York September 10, 2013. Wednesday marks the 12th anniversary of the attacks on September 11, 2001.ADREES LATIF/Reuters
A rose and a note is left in an inscribed name at the North Pool of the 9/11 Memorial at Ground Zero, the site of the September 11, 2001 attacks, in New York September 10, 2013.ADREES LATIF/Reuters
A woman reflects while standing at the South Pool of the 9/11 Memorial at Ground Zero, the site of the September 11, 2001 attacks, in New York September 10, 2013.ADREES LATIF/Reuters
A member of the Port Authority Emergency Services Unit monitors Ground Zero during memorial ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.ANDREW BURTON
Former Mayor Rudy Giuliani (L) and New York City Mayor Michael Bloomberg attend a ceremony at the 9/11 Memorial marking the 12th anniversary of the attacks on the World Trade Center in New York September 11, 2013.DAVID HANDSCHUH
Mija Quigley, of Princeton Junction, N.J., embraces the name of her son, Patrick Quigley, during ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York, Wednesday, Sept. 11, 2013. Patrick Quigley died aboard Flight 175 when it crashed into the South Tower on 9/11CHRIS PEDOTA
A member of the audience cries at an event commemorating the 12th anniversary of the 9/11 attacks, at the Pentagon near Washington, September 11, 2013.JASON REED
President Barack Obama, accompanied by Defense Secretary Chuck Hagel, wipes his face as he speaks during a 9/11 remembrance ceremony at the Pentagon, Wednesday, Sept. 11, 2013MANUEL BALCE CENETA
Left to right, U.S. President Barack Obama, Secretary of Defense Chuck Hagel, and Chairman of the Joint Chiefs of Staff U.S. Army General Martin Dempsey attend remembrance ceremonies for 9/11 at the Pentagon 9/11 Memorial in Washington September 11, 2013. The large flag in background marks the point of impact where a jetliner crashed into the Pentagon 12 years ago today.GARY CAMERON
A woman prays at the edge of the North Pool at the 9/11 Memorial during a ceremony marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.JUSTIN LANE
A flower is left along the North Pool of the 9/11 Memorial during a ceremony marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.JUSTIN LANE
Mercedes Arias listens as they read the name of her father Joseph Amatuccio at the 9/11 Memorial during ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.ALEJANDRA VILLA
Left to right, U.S. President Barack Obama, Secretary of Defense Chuck Hagel and Chairman of the Joint Chiefs of Staff Martin Dempsey participate in an event on the 12th anniversary of the 9/11 attacks at the Pentagon near Washington, September 11, 2013.JASON REED
Flowers and pictures are left along the North Pool of the 9/11 Memorial during a ceremony marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.JUSTIN LANE
Traders pause during a moment of silence to honor victims of the 9/11 attacks on the World Trade Center, on the floor of the New York Stock Exchange September 11, 2013.LUCAS JACKSON
A note is left on the name of a victim etched in the wall at the North Pool of the 9/11 Memorial during a ceremony marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.JUSTIN LANE
U.S. President Barack Obama lays a wreath before remembrance ceremonies for 9/11 victims at the Pentagon 9/11 Memorial in Washington September 11, 2013.GARY CAMERON
A woman holds a picture of a fire fighter during memorial ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York September 11, 2013.ANDREW BURTON