9/11 in Photos: A day that will never be forgotten.

It has been 22 years since al-Qaeda carried out a horrendous terrorist attack against the United States. It is a day that, no matter where you were in the world at that time, you are unlikely to forget. It is etched in all of our minds, as are the heroic efforts of those who gave their lives to save others on that terrible day. Join us as we take a look at the historic photos of how the events unfolded on 9/11.

September 11, 2001. It was 8:46 in the morning in New York when American Airlines Flight 11 (coming from Boston's Logan Airport) crashed into the North Tower of the World Trade Center.
At that first moment, in the streets, the looks on people's faces were those of surprise. They were unaware still that this supposed accident was a terrorist attack.

In those first moments, curiosity drove the New Yorkers to the street. The devastation was unimaginable, and they were trying to wrap their heads around it. Many also thought, in horror, of the thousands of people working the World Trade Center every day.

At 09:03, United Airlines Flight 175 crashed into the South Tower of the World Trade Center. Eyewitnesses, news stations and TV viewers had been watching the building, so the blast was in everyone's eyeshot. The sequence of events was broadcast live on television and the entire planet could see the terrorist attack in real time.

Paralyzed by surprise and panic, people on the streets were staring at the flames. Both towers were burning and New York was in a state of shock. Meanwhile, there was more disturbing news coming in: bombs in other places, hijacked planes...

Suddenly, around ten in the morning, the situation in Lower Manhattan took another terrible turn. The South Tower of the World Trade Center came crumbling down. Some time later, the North Tower would also collapse.

The images that arrived from New York that September 11 were incredible, like something out of a movie. It was the largest attack suffered by the United States on its own territory since Pearl Harbor.

The North Tower fell about half an hour after the South Tower. By then, witnesses in the area - called Ground Zero - were already fleeing the scene. From afar (this image was made in New Jersey), Lower Manhattan disappeared behind a big cloud of smoke.

The ash from the ruined buildings covered the city centre, its fog becoming a symbol of terror.

Two other planes had also been hijacked. One crashed into the western wing of the Pentagon in Washington, DC. The other plane also appeared to be headed towards Wasington.

Suddenly, iconic places in the United States seemed like war zones.

What exactly happened inside the other plane (United Airlines 93) is unknown. Later investigations determined that the crew and passengers confronted the terrorists before the plane crashed into an uninhabited area of Pennsylvania.

Within a few hours 2,996 people died. The devastating attack would soon be claimed by Al Qaeda, the radical Islamist network led by Osama Bin Laden.

The most powerful country in the world suddenly appeared vulnerable. Its most iconic city, New York, was plunged into ruins and ash floated through the air for days.

The famous New York skyline had become a scene of war.

The heroes and heroines of September 11 included the New York City public workers, such as the firefighters who died while trying to rescue the desperate people trapped in the World Trade Center.

The day itself and the weeks after 9/11 were traumatic for rescue workers, police forces, and fire brigades.

The ruins of the World Trade Center quickly became a place to commemorate the attacks and their victims.

George W. Bush's presidency completely changed course with the 9/11 attacks. The war against terror became his main policy. His administration began a war in Afghanistan that, 20 years later, would end in defeat and withdrawal for U.S. and allied forces.

Pictures of details in Ground Zero express the brutality of the violence. This doll was found among the remains of the World Trade Center.

The September 11 attack was traumatic for the United States, but it also changed the world order. It rang in a period of wars, including those in Iraq and Syria, as well as other attacks in Madrid and London. As a consequence, it gave rise to a permanent quest for security in the face of jihadist terrorist threats.

From the air, the skyline of Manhattan Island could be seen as marked by the smoke from the attack. On September 11, everything changed. Many of us will still remember exactly where we were on the moment we witnessed it.