On Pennsylvania Ave between Ninth and Tenth sts NW, just north of the Mall; closest Metro stop is Federal Triangle. Hour-long tours every 20-30min, Mon-Fri 8.45am-4.15pm, no reservations. Admission free. tel 202/324-3447,

A fortress-like modern building on Pennsylvania Avenue holds the headquarters of the FBI - the Federal Bureau of Investigation , the nation's elite law-enforcement organization. Set up in 1908, the FBI came into its own chasing bootleggers and bank robbers like Al Capone and Machine Gun Kelly during the 1920s and 1930s. Hordes of visitors queue outside, sometimes for more than an hour, to join tours past displays on the infamous gangsters and dangerous subversives from whom the FBI shields the American people (they kept extensive files on Dr Martin Luther King Jr). Ideology aside (the FBI has only just begun to emerge from the shadow of its longtime iron-fisted director, J. Edgar Hoover), the tours rush you through an overview of fingerprinting, ballistics testing and other crime-fighting techniques. What really brings the crowds in, however, is the climactic display of sharpshooting and firepower: agents blast away at cut-out targets with a battery of small arms and automatic weapons.

Federal Bureau of Investigation

• Federal Bureau of Investigation

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