1/8A man walks through the 9/11 Empty Sky memorial at sunrise across from New York's Lower Manhattan and One World Trade Center in Liberty State Park in Jersey City, New Jersey, September 11, 2013.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
2/8FDNY Firefighter Mike Bellantoni of New York prepares a memento at the Firefighter's Memorial adjacent to the World Trade Center, Sept. 11, 2013 before the start of the official ceremonies at the 9/11 Memorial nearby.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
3/8Britain's Prince Harry (L) and Prince William (R) take part in a trade on the trading floor of BGC Partners. BGC holds a Charity Day each year to commemorate the 658 employees who lost their lives in the 9/11 attacks on the World Trade Centre in New York. London, September 11, 2013.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
4/8Former Mayor Rudy Giuliani (2nd L) and New York City Mayor Michael Bloomberg (2nd R) 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.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
5/8A woman looks out at New York's Lower Manhattan and One World Trade Center from inside the 9/11 Empty Sky memorial at Liberty State Park in Jersey City, New Jersey, September 11, 2013.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
6/8U.S. President Barack Obama, first lady Michelle Obama, Vice President Joe Biden and Jill Biden (L-R) pause for a moment of silence on the 12th anniversary of the attacks of September 11, 2001, on the South Lawn of the White House in Washington.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
7/8People observe a moment of silence honoring the victims of the September 11 attacks outside the World Trade Center site in New York, September 11, 2013.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
8/8Two people with shirts commemorating New York City Fire Department firefighter Frankie Esposito sit at the South reflecting pool at the 9/11 Memorial during ceremonies marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York.
Solemn memorials are being held in New York, Washington and Pennsylvania to honor the victims of the September 11, 2001 terror attacks.
