Answer:
The event considered to be the "spark" that started the "War on Terrorism" was the 9/11 attacks.
Explanation:
The 9/11 attacks took place on September 11, 2001. 2,996 people died and over 25,000 other people were injured during these attacks.
The United States had the suspicion that al-Qaeda had been responsible for these attacks. Thus, the United States decided to respond through Afghanistan's invasion to dismiss the Taliban. As a result of these attacks, many countries decided to reinforce their security through their intelligence agencies.
In the beginning, Osama bin Laden who was the leader of al-Qaeda did not admit his participation in the attacks but in 2004 he demanded responsibility in the attacks. The 9/11 attacks seriously affected not only New York's economy but it also affected global markets, and one important effect of this was the fact that Wall Street had to close.
