The term "911" typically refers to either the emergency telephone number or the September 11 attacks.
- The emergency telephone number 911 was first implemented in the United States in 1968. The first 911 call was made in Haleyville, Alabama, on February 16, 1968, marking the beginning of the 911 emergency system nationwide.
- The "9/11" attacks refer to the terrorist attacks that occurred on September 11, 2001, where four coordinated Islamist terrorist suicide attacks were carried out by al-Qaeda against the United States.
If the question is about the emergency number, 911 was established in 1968. If it refers to the historic terrorist attacks, 9/11 happened on September 11, 2001.
