In Pics: Remembering 9/11, 19 years on

A New York City fireman calls for 10 more rescue workers to make their way into the rubble of the World Trade Center September 14, 2001 days after the September 11, 2001 terrorist attack. Credit: Getty Images

A man stands in the rubble, and calls out asking if anyone needs help, after the collapse of the first World Trade Center Tower in New York. Credit: AFP Photo

A firefighter breaks down after the World Trade Center buildings collapsed September 11, 2001 after two hijacked airplanes slammed into the twin towers in a terrorist attack that killed some 3,000 people. Credit: Getty Images

The World Trade Center - Cortlandt Street subway station is seen in New York. Credit: AFP Photo

US President Donald Trump and First Lady Melania Trump attend the 9/11 observance at the National 9/11 Pentagon Memorial in Arlington, Virginia. Credit: Reuters Photo

Flowers sit in names at the north reflecting pool at the National 9/11 Memorial the day before the 19th anniversary of attacks in the Manhattan borough of New York City. Credit: Reuters Photo

Democratic presidential candidate and former Vice President Joe Biden attends the 19th anniversary of the 9/11 attacks with his wife Jill Biden and New York Governor Andrew Cuomo at the National September 11 Memorial & Museum in New York City. Credit: Reuters Photo