After the September 11, 2001 attacks, the U.S. government responded with immediate action (including rescue operations at the site of the World Trade Center and grounding civilian aircraft), and long-term action, including investigations, legislative changes, military action and restoration projects.
Depending on how broadly the term is defined, the roots and practice of terrorism can be traced at least to the 1st-century AD Sicarii Zealots, though some dispute whether the group, which assassinated collaborators with Roman rule in the province of Judea, was in fact terrorist.
9/11 was caused by al-qaeda/ bin laden and The attacks killed 2,996 people, injured over 6,000 others, and caused at least $10 billion in infrastructure and property damage.
