18 years of 9/11 attack: Tributes

A picture of a man who lost his life in the attacks is seen at ground zero while the Tribute in Light rises in the background, in Lower Manhattan, Wednesday, September 11, 2019, in New York. Each year the city shines the powerful columns of light into the sky to represent the fallen twin towers of the World Trade Centre. (Photo: AP)

US President Donald Trump and First Lady Melania Trump participate in a moment of silence honouring the victims of the 9/11 attacks. (Photo: PTI)

Norma Molina, of San Antonio, Texas, leaves flowers by the names of firefighters from Engine 33 at the September 11 Memorial, Monday, Sept. 9, 2019, in New York. Her boyfriend Robert Edward Evans, a member of Engine 33, was killed in the north tower of the World Trade Centre on September 11, 2001. (Photo: AP)

A US flag hanging from a steel girder, damaged in the September 11, 2001 attacks on the World Trade Centre, blows in the breeze at a memorial in Jersey City, New Jersey, September 11, 2019 as the sun rises behind One World Trade Centre building and the re-developed area where the Twin Towers of World Trade Centre once stood in New York City on the 18th anniversary of the attacks. (Photo: AP)

Yuma Fire Department Captain Brandon Case, foreground, carrying American flag, along with other YFD personnel, civilians and Marine Corps Air Station-Yuma Aircraft Rescue and Firefighting personnel, move down 4th Avenue during the morning's fifth annual "Tunnel to Towers Run," Wednesday, Sept. 11, 2019, in honor of New York City Fire Department firefighter Stephen Siller, who died in the terrorist attacks on the World Trade Centre on September 11, 2001. (Photo: AP)

In this September 11, 2001, file photo, smoke rises from the burning twin towers of the World Trade Centre after hijacked planes crashed into the towers in New York City. (Photo: AP)

In this Septemer 11, 2001 file photo, firefighters work beneath the destroyed mullions, the vertical struts which once faced the outer walls of the World Trade Centre towers, after a terrorist attack on the twin towers in New York. (Photo: AP)

Spectators and photographers look across the Hudson River from Jersey City, New Jersey, at the 9/11 tribute lights in New York City on the 18th anniversary, Wednesday, September 11, 2019, of the attacks on the twin towers of the World Trade Centre. (Photo: AP)