Memories of 9/11 terrorist attack

People run from a collapsing World Trade Center tower in New York. For over a decade after the autumn of 2001, America, with its allies, has been at war against factions of Islamist militants and terrorists, including the Taliban and al Qaida, as well as offshoots in Yemen, Somalia and elsewhere.

The early stages of reconstruction starting at the World Trade Center site in New York. Thirteen years after 9/11 forever changed the New York skyline, officials say developments at the World Trade Center are on track and on budget.

The National September 11 Memorial and Museum, shows a pair of high heel shoes worn by JoAnne JoJo Capestro while descending 87 floors of stairs to escape a World Trade center tower on Sept. 11, 2001. The shoes are among the clothes, wallets, helmets, and other personal effects donated to the museum by survivors and those who worked at the site in the attacks' aftermath.

1 World Trade Center, center, is viewed from the 62nd floor of Four World Trade Center in New York. On the thirteenth anniversary of the attacks of Sept. 11, 2001, 1 World Trade Center will soon open to its first tenants and Four World Trade Center is open.

A pair of boots with melted soles that Carol Orazem wore while working at the World Trade Center after the terrorist attacks of 2001. Orazem was a New York City police detective when the towers were destroyed. She donated the boots she wore while working at the World Trade Center rescue/recovery operation to the National September 11 Memorial and Museum.

The Tribute in Light rises above buildings during a test in New York. While the plaza at the National September 11 Memorial and Museum will be closed to the public, during the September 11 commemoration ceremony and much of the rest of the day, it will be open from 6 p.m. to midnight for those who want to pay respects and view one of the anniversary's most evocative traditions, the twin beams called the Tribute in Light.

The Tribute in Light rises behind buildings adjacent to the World Trade Center in New York. The art installation consists of 88 searchlights aiming skyward in two columns, in memory of the former twin towers. Four World Trade Center is at left. Thirteen years after 9/11 forever changed the New York skyline, officials say developments at the World Trade Center are on track and on budget.