Posted with permission from International Business Times

Monday marks the 16th anniversary of the deadly attacks on Sept. 11, 2001, that shook the United States.

Even as the country is ravaged by multiple hurricanes, thousands of survivors, relatives of victims and rescuers are expected to gather Monday at the World Trade Center to mark the anniversary. Meanwhile, President Donald Trump and First Lady Melania Trump are scheduled to observe a minute of silence at around the time the first of the three airplanes hit the Twin Towers in Manhattan, according to reports.

In one of the worst attacks on American soil, on Sept. 11, 2001, two airplanes controlled by hijackers crashed into the World Trade Center, Pentagon and a field near Shanksville, Pennsylvania, killing almost 3000 people and injuring more than 6000. It is thought that the third plane was intended to crash into the White House or the Capitol building in Washington, D.C.

Speaking after the attacks in 2001, the then-President George W. Bush said in an address: "The pictures of airplanes flying into buildings, fires burning, huge structures collapsing, have filled us with disbelief, terrible sadness, and a quiet, unyielding anger. These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed; our country is strong."

Visuals and pictures of the attacks and their aftermath remain some of the most infamous images of American history, serving as a somber reminder of one of the country's darkest moments. On the 16th anniversary of the attack, here is a look back at some of these pictures. 

Rescue workers searching for victims at Ground Zero after the collapse of the World Trade Center in New York City, on Sept. 13, 2001. Photo: Getty Images/Frank Schwere Smoke pours from the twin towers of the World Trade Center after they were hit by two hijacked airliners in a terrorist attack Sept. 11, 2001, in New York City. Photo: Getty Images/ Robert Giroux/ A firefighter breaks down after the World Trade Center buildings collapse Sept. 11, 2001. Photo: Getty Images/ Mario Tama Smoke comes out from the Southwest E-ring of the Pentagon building Sept. 11, 2001, in Arlington, Virginia., after a plane crashed into the building and set off a huge explosion. Photo: Getty Images/Alex Wong A survivor sits outside the World Trade Center after two planes hit the building Sept. 11, 2001, in New York City. Photo: Getty Images/Jose Jimenez/Primera Hora U.S. President George W. Bush (R) being informed by his chief of staff Andrew Card of the attacks on the World Trade Center in New York during an early morning school reading event in Sarasota, Florida. Photo: Paul. J. Richards /AFP/Getty Images

Homeland Security adviser Tom Bossert told reporters on Friday that president will be presented with "a comprehensive picture of the terrorist threat environment and what we're doing to counter it from his senior officials on 9/11." He added: "No terrorist should view us as vulnerable right now, farthest thing from the truth. Second, there is no actionable, credible threat to the United States right now."

The president is also expected to attend a Pentagon ceremony led by Defense Secretary Jim Mattis and General Joseph Dunford, chairman of the Joint Chiefs of Staff, to pay respects to the victims. Vice President Mike Pence and US Secretary of the Interior Ryan Zinke are scheduled to deliver remarks at the Flight 93 National Memorial near Shanksville, Pennsylvania. 

On Sept. 8, Trump had proclaimed the day of the attacks to be "Patriot Day" to honor the innocent lives lost and those who aided "their fellow citizens in America's time of need."

“On this anniversary, I invite all Americans to thank our Nation's incredible service members and first responders, who are on the front lines of our fight against terrorism.  We will always remember the sacrifices made in defense of our people, our country, and our freedom,” he said in a statement.

The statement added: “We rededicate ourselves to the ideals that define our country and unite us as one, as we commemorate all the heroes who lost their lives saving others.”