President Trump, first lady Melania Trump and Stephen Clark, the superintendent of the National Parks of Western Pennsylvania, walk through the Flight 93 National Memorial in Shanksville, Pa., on Tuesday.
WTC Cortlandt subway station reopened in New York on Saturday, nearly 17 years after it was destroyed during the terrorist attack on the World Trade Center on Sept. 11, 2001.
New York City Mayor Bill de Blasio speaks to Democratic presidential nominee Hillary Clinton during a memorial service at the National September 11 Memorial and Museum.
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Russell Mercer replaces old U.S. flags with new ones at the Flushing World Trade Center Memorial at Flushing Cemetery in New York City. His stepson, Scott Kopytko, was killed on Sept. 11.
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A construction worker looks up at One World Trade Center in New York City, the central skyscraper under construction at Ground Zero, a year before its 2013 completion.
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Members of the Taliban militia ride in vehicles during Afghanistan's annual Independence Day parade in Kabul on Aug. 19, 2001. Afghanistan was largely cut off from the world during the Taliban's rule from 1996 to 2001. That changed dramatically after the Sept. 11 attacks.
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Three World Trade Center is under construction near One World Trade Center, which was completed in 2013. The new building stands 1,079 feet tall, and its topping-out ceremony was held in June.
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Relatives of victims of the Sept. 11 attacks are periodically flown down to Guantanamo Bay, Cuba, to witness court proceedings against five men accused of plotting the attacks. For the witnesses of the most recent court session, the experience raised questions about justice, humanity and the ethics of the death penalty.
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An artist's image of the wall that will separate the public from the repository where unidentified remains will be kept at the National September 11 Memorial Museum in Manhattan.
One World Trade Center stands at its full height of 1,776 feet Friday, after a crane lifted its spire into place. The New York City skyline is seen here from the Heights neighborhood of Jersey City, N.J.