Introduction:
On September 11, 2001, a tragic event occurred in New York City that shook the world. The World Trade Center towers, also known as the Twin Towers, were the target of a terrorist attack that involved the crashing of aircraft. The attack was orchestrated by the extremist group Al-Qaeda, causing immense loss of life and destruction.

Explanation:

1. Attack Details:
- On the morning of September 11, 2001, 19 terrorists hijacked four commercial airplanes.
- Two of these airplanes were flown into the North and South Towers of the World Trade Center complex in New York City.
- The hijackers intentionally crashed American Airlines Flight 11 into the North Tower at 8:46 a.m. Eastern Time.
- Approximately 17 minutes later, United Airlines Flight 175 was flown into the South Tower at 9:03 a.m. Eastern Time.

2. Impact:
- The impact of these aircraft crashing into the towers was catastrophic.
- The structural integrity of both towers was severely compromised, leading to their subsequent collapse.
- The North Tower collapsed at 10:28 a.m., approximately 1 hour and 42 minutes after being hit.
- The South Tower collapsed shortly after at 9:59 a.m., approximately 56 minutes after being hit.
- These collapses resulted in the loss of thousands of lives and caused extensive damage to the surrounding area.

3. Other Attacks:
- While the focus of this question is on the World Trade Center towers, it is important to note that the other two hijacked planes were involved in separate attacks.
- American Airlines Flight 77 was flown into the Pentagon in Arlington, Virginia, at 9:37 a.m.
- United Airlines Flight 93, which was likely targeting another high-profile location, crashed into a field in Pennsylvania after passengers attempted to regain control of the plane.

Conclusion:
In summary, two aircraft crashed into the World Trade Center towers in New York City on September 11, 2001. The impact of these crashes resulted in the collapse of both towers and caused widespread devastation. This tragic event forever changed the world and serves as a somber reminder of the need for global unity in the face of terrorism.