$9.3 billion - Insurance claims arising from the 9/11 attacks.

Cleanup at ground zero:

Cleanup at ground zero officially ends on May 30, 2002.

It took 3.1 million hours of labor to clean up 1.8 million tons of debris.

The total cost of cleanup was $750 million.

Homeland Security:

The Department of Homeland Security is created in response to Sept. 11.

It merges 22 governmental agencies into one, including the Customs Service, the Immigration and Naturalization Service, the U.S. Coast Guard and the Federal Emergency Management Agency.

The Dept. of Homeland Security places 130 U.S. inspectors at ports in major European, Asian and Muslim nations, as well as strategically-located ports, to inspect cargo for nuclear, chemical or biological weapons being smuggled into the U.S.

The Homeland Security Advisory System is introduced on March 12, 2002.

The nationwide alert status has been raised from its current level of yellow (elevated) to orange (high) on five occasions. It has never been below yellow. New York City has remained at orange (high) since 9/11. In August 2006, the threat level for flights from the United Kingdom to the U.S. is raised to red, the first time that threat level has been used.

On April 26, 2011, the National Terrorism Advisory System (NTAS) replaces the color-coded Homeland Security Advisory System (HSAS). NTAS utilizes a vocabulary system including terms Elevated and Imminent.