On the morning of September 11, 2001, 19 men made sure the day would live in infamy. The men, all members of the militant Islamist organization al-Qaeda, hijacked 4 airplanes with the goal of crashing into four prominent buildings, carrying out what would be the largest and deadliest terror attacks on American soil.

Two of the planes hit the Twin Towers in Lower Manhattan, New York, while a third hit the Pentagon in Virginia killing nearly 3,000 people. The massive loss of life would have been higher, if not for the efforts of passengers and flight crew of the fourth aircraft who were able to divert the flight from its intended target, ultimately crashing the plane into a field in Pennsylvania. Investigators later on determined that the target of the airliner was either the White House or the US Capitol in Washington.

The attacks triggered America’s war on terror, one of its longest military campaigns ever, as it targeted what it termed as extremist groups primarily al-Qaeda and its founder Osama bin Laden.

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Twenty years on, the effects of the attacks can still be felt around the world with the US leaving Afghanistan, where bin-Laden had previously operated, only at the end of August and the ultra-conservative Taliban returning to power.

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Here are some images from those horrific moments forever dubbed “9/11”.

The twin towers of the World Trade Center billow smoke after hijacked airliners crashed into them early 11 September, 2001. The suspected terrorist attack has caused the collapsed of both towers. Henry Ray Abrams, AFP

A fiery blast rocks the World Trade Center after being hit by two planes on September 11, 2001 in New York City. Spencer Platt/, etty Images via AFP

People run away as the North Tower of the World Trade Center collapses after a hijacked airliner hit the building on September 11, 2001 in New York City. Jose Jimenez/Primera Hora, Getty Images via AFP

A police officer (R) and others walking up Park Row from St. Paul's Chapel (background), a few blocks from the World Trade Center site, in streets covered with debris in New York City shortly after the two towers collapsed on September 11, 2001. Stan Honda, AFP

A hijacked United Airlines Flight 175 from Boston crashes into the south tower of the World Trade Center at 9:03 a.m. in New York City on Septmeber 11, 2001. Spencer Platt, Getty Images via AFP

The World Trade Center in New York City burns in New York, U.S., early September 11, 2001. Jeff Christensen, Reuters

U.S. President George W. Bush listens as White House Chief of Staff Andrew Card informs him of a second plane hitting the World Trade Center while Bush was conducting a reading seminar at the Emma E. Booker Elementary School, in Sarasota, Florida on September 11, 2001. Win McNamee, Reuters

The second tower of the World Trade Center bursts into flames after being hit by a hijacked airplane in New York, U.S. on September 11, 2001. The Brooklyn bridge is seen in the foreground. Sara K. Schwittek, Reuters

People look out of the burning North tower of the World Trade Center in New York City, New York, U.S. on September 11, 2001. Jeff Christensen, Reuters

Firefighters walk towards one of the tower at the World Trade Center before it collapsed after a plane hit the building on September 11, 2001 in New York City. Jose Jimenez/Primera Hora, Getty Images via AFP

A man stands in the rubble, and calls out asking if anyone needs help, after the collapse of the first World Trade Center Tower 11 September, 2001, in New York. Two hijacked planes crashed into the twin towers causing the collapse of both. Doug Kanter, AFP

Firefighters make their way through the rubble of the World Trade Center on 11 September 2001 in New York after two hijacked planes flew into the landmark skyscrapers. Doug Kanter, AFP

A firefighter walks through rubble of the twin towers of the World Trade Center as a US flag hangs from a traffic light post 11 September, 2001, in New York. Doug Kanter, AFP

People walk in the street in the area where the World Trade Center buildings collapsed on September 11, 2001 after two airplanes slammed into the twin towers in a terrorist attack. Mario Tama, Getty Images via AFP

Rescue workers survey damage to the World Trade Center on September 11, 2001 in New York. Two planes controlled by hijackers crashed into the twin towers of the center destroying the buildings. At almost the same time, another hijacked plane flew into the Pentagon in Washington, DC. Doug Kanter, AFP

A man with a fire extinguisher walks through rubble after the collapse of the first World Trade Center Tower on September 11, 2001, in New York. The man was shouting as he walked looking for victims who needed assistance. Both towers collapsed after being hit by hijacked passengers planes. Doug Kanter, AFP

Smoke is seen at the towers of the World Trade Center shortly after being struck by a hijacked commercial aircraft, in New York, U.S. on September 11, 2001. Brad Rickerby, Reuters

A rescue helicopter surveys damage to the Pentagon as firefighters battle flames after an airplane crashed into the U.S. military headquarters outside of Washington, U.S. on September 11, 2001. Larry Downing Reuters

The remaining tower of New York's World Trade Center, Tower 2, dissolves in a cloud of dust and debris about half an hour after the first twin tower collapsed, as seen from Jersey City, New Jersey, U.S. on September 11, 2001. Ray Stubblebine, Reuters

In this handout provided by the Federal Bureau of Investigation (FBI), first responders on scene following an attack at the Pentagon on September 11, 2001 in Arlington, Virginia in this undated image. American Airlines Flight 77 was hijacked by al Qaeda terrorists who flew it in to the building killing 184 people. Federal Bureau of Investigation via Getty Images/AFP

Rescue workers carry the mortally injured New York City Fire Department chaplain, the Rev. Mychal Judge, from the wreckage of the World Trade Center in New York, U.S., September 11, 2001. The chaplain was crushed to death by falling debris while giving a man last rites in the trade center. Shannon Stapleton, Reuters

Firemen work around the World Trade Center after both towers collapsed in New York, U.S. on September 11, 2001. Peter Morgan, Reuters

A fire truck sits in front of the damaged area of the Pentagon Building as fire fighters and rescue workers continue to battle smoke at the U.S. military headquarters outside of Washington, U.S. on September 12, 2001. Larry Downing, Reuters

New York City firefighters and other emergency personnel battle building blaze after the World Trade Center buildings collapsed in New York, U.S. on September 11, 2001. Reuters

New York City firefighters pour water on the wreckage of 7 World Trade Center in New York, U.S., early September 12, 2001. Mike Segar, Reuters

Television crews prepare for their broadcasts as smoke and ash from the destroyed World Trade Center rises over the southern end of New York City's Manhattan as seen from Jersey City, New Jersey in the early morning of 12 September, 2001. Terrorists hijacked two commercial airliners and crashed them into each of the towers of the Trade Center. Tannen Maury, AFP

A New York City fireman calls for more rescue workers to make their way into the rubble of the World Trade Center in New York, U.S. on September 15, 2001. Journalist 1st Class Preston Keres/U.S. Navy Photo/Handout via Reuters

A New York City firefighter places flowers and mementos from family members of the victims of the World Trade Center attacks, amidst the wreckage, following a memorial service for the victims of the September 11 attack at the site in New York, U.S. on October 28, 2001. Mike Segar, Reuters