The national security depends on our defense installations and facilities being in the right place, at the right time, with the right qualities and capacities to protect our national resources. Those resources have never been more important as America fights terrorists who plan and carry out attacks on our facilities and our people. Our military servicemembers and civilians operate in every time zone and in every climate. More than 450,000 employees are overseas, both afloat and ashore. The Defense Department manages an inventory of installations and facilities to keep Americans safe. The Department’s physical plant is huge by any standard, consisting of more than several hundred thousand individual buildings and structures located at more than 5,000 different locations or sites. When all sites are added together, the Department of Defense utilizes over 30 million acres of land. These sites range from the very small in size such as unoccupied sites supporting a single navigational aid that sit on less than one-half acre, to the Army's vast White Sands Missile Range in New Mexico with over 3.6 million acres, or the Navy’s large complex of installations at Norfolk, Virginia with more than 78,000 employees.