How did the world trade center attack happen?

On September 11, 2001, four coordinated terrorist attacks were carried out by the Islamic terrorist group Al-Qaeda against the United States. Two of these attacks involved the hijacking of commercial airliners that were deliberately crashed into the North and South towers of the World Trade Center in New York City. Here's a timeline of the events related to the World Trade Center attacks:

7:59 AM EDT: American Airlines Flight 11, a Boeing 767, departs from Boston's Logan International Airport en route to Los Angeles.

8:14 AM EDT: United Airlines Flight 175, also a Boeing 767, departs from Boston's Logan International Airport bound for Los Angeles.

8:46 AM EDT: American Airlines Flight 11 crashes into the North Tower of the World Trade Center in Manhattan, New York City. The impact occurs between floors 93 and 99, causing an intense fire and structural damage to the building.

9:03 AM EDT: United Airlines Flight 175 crashes into the South Tower of the World Trade Center, between floors 77 and 85. This collision further escalates the fire and damage in the South Tower.

9:37 AM EDT: The impact and resulting fire cause the South Tower to collapse, becoming the first building to collapse on 9/11.

10:28 AM EDT: American Airlines Flight 77, a Boeing 757, crashes into the Pentagon in Arlington, Virginia, near Washington, D.C. The plane hits the western side of the Pentagon, causing significant damage and loss of life.

10:54 AM EDT: United Airlines Flight 93, a Boeing 757, crashes in a field near Shanksville, Pennsylvania. Flight 93 had likely been intended to strike a target in Washington, D.C., but the passengers attempted to regain control of the plane from the hijackers, leading to its crash before reaching its intended target.

Noon EDT: The North Tower of the World Trade Center collapses after burning for over two hours, becoming the second building to fall.

4:00 PM EDT: The fire in the World Trade Center complex is finally extinguished.

The attacks on the World Trade Center resulted in the deaths of nearly 3,000 people, including passengers and crew members on the four hijacked planes, people working in the World Trade Center towers, and emergency responders who were assisting in rescue efforts. The aftermath of 9/11 triggered a global response in the form of increased security measures, the War on Terror, and various investigations and efforts to combat terrorism.