September 11 Anniversary

Civil War re-enactor Cpl. Robert Fuller Houston with the 3rd Regiment Infantry, lowers his head during a prayer at a ceremony, Sept. 11, 2013, marking the 12th anniversary of the 9/11 terrorist attacks at the Betsy Ross House in Philadelphia.

Riot police advance on a pro-democracy protest encampment in the Mong Kok district of Hong Kong early, Oct. 19, 2014.

Detroit Fire Department Lt. Gerod Funderburg rings a bell during a ceremony in Detroit, Sept. 11, 2013, marking the 12th anniversary of the 9/11 terrorist attacks.

Red roses are placed next to names of victims of the Sept. 11, 2001 terrorist attacks on the U.S. at a memorial site during a ceremony marking the 12th anniversary of 9/11 outside Jerusalem, Sept. 11, 2013. 

A man walks through the 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, Sept. 11, 2013. 

FDNY Firefighter Mike Bellantoni prepares a memento at the Firefighter's Memorial adjacent to the One World Trade Center, Sept. 11, 2013.

Britain's Prince Harry and Prince William take part in a trade on the floor of BGC Partners as part of a 9/11 commemoration, London, Sept. 11, 2013. 

Former Mayor Rudy Giuliani 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, Sept. 11, 2013.

A woman looks out at New York's Lower Manhattan and One World Trade Center from inside the Empty Sky memorial at Liberty State Park in Jersey City, New Jersey, Sept. 11, 2013.

Grissel Valentin (L) and Eileen Esquilin, who both lost family members in the 9/11 attacks, embrace at the edge of 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.

U.S. President Barack Obama, first lady Michelle Obama, Vice President Joe Biden and Jill Biden pause for a moment of silence on the 12th anniversary of the September 11 attacks on the South Lawn of the White House.

A woman wipes her eyes after reading the name of her brother, Bobby Hughes, as friends and relatives of the victims of the 9/11 terrorist attacks gather at the National September 11 Memorial at the World Trade Center site, Sept. 11, 2013.

People observe a moment of silence honoring the victims of the September 11 attacks outside the World Trade Center site in New York, Sept. 11, 2013.

Navy Quartermaster Matthew Konchan of Johnstown, Pa., stands in a field of black-eyed susans as he waits to participate in a wreath laying ceremony with Secretary of the Interior Sally Jewell during a memorial service at the Flight 93 National Memorial, Sept. 11, 2013.

A woman touches the stone with names of the 9/11 victims at the 9/11 Memorial during ceremonies marking the 12th anniversary of the attacks on the World Trade Center in New York, Sept. 11, 2013.

Indonesia's President Joko Widodo, left, walks with his predecessor Susilo Bambang Yudhoyono at the presidential palace in Jakarta, Indonesia, Oct. 20, 2014.

Two 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 attacks.

Visitors to the Flight 93 National Memorial participate in a sunset ceremony with a giant flag memorializing Flight 93, Sept. 10, 2013.