Built during the Great Depression, Hoover Dam is one of America's great historical landmarks. Securing the dam and providing a safe experience for the many visitors requires a robust security program.Security officials from Reclamation gave CSOonline a tour of the facilities in mid-September, showing us highlights of the various security programs.SEE IMAGES FROM INSIDE THE HOOVER DAMThe Art Deco concrete structure, located about an hour outside Las Vegas in the Black Canyon of the Colorado River, straddling the Nevada-Arizona border, was the largest hydroelectric generating station, and the world's largest concrete structure when completed in 1936. Over 75 years later, Hoover Dam continues its multiple roles in flood control, power generation, and as a major supplier of water in the Southwestern U.S.See also: New Cyber-Security Standards for N. American Power SystemThe site is practically a city in itself, with its own police department and other security services. Some security procedures and systems, designed to deter, detect, and defend the facility were visible; however, much of the security activity is hidden.Guiding us was Peter Gregson, regional security officer for Reclamation's Lower Colorado Region.The tour began at the Hoover Dam Police Department in the Security Command Center, where the security staff monitors the various security, access control, and communications systems on a 24\/7 basis.In addition to the Hoover Dam police force, the dam employs additional contract security personnel to man vehicle checkpoints on the Nevada and Arizona entrance points.Gregson said many of the security controls, including such things as the checkpoints and command center, were instituted in direct response to the 9-11 terrorist attacks.Commercial vehicle traffic across the dam is restricted. At the checkpoints U-Haul-type vehicles are allowed after a search is conducted, while semi-trailer trucks, buses carrying luggage, and enclosed-box trucks are prohibited from crossing the road atop the dam (That traffic is diverted south to a Colorado River bridge at Laughlin, Nevada). "Cars are searched on a random basis or if there is a reasonable suspicion," he said.Security training and exercises for the police and security officers is conducted frequently often with other federal and local law enforcement agencies to provide them with familiarity of the facility. The Hoover dam police department partners with many of the neighboring law enforcement agencies. "They conduct joint training with us," Gregson said.Meanwhile, a new Hoover Dam Bypass and bridge is under construction, scheduled for completion next year. It will divert U.S. 93 traffic downstream from the dam. Once the bypass is completed, the road atop the dam will no longer be a direct route between Nevada and Arizona.Those managing dam security are bound by a host of government regulations and security standards including Homeland Security Presidential Directives and regulations and standards enforced by the North American Electrical Reliability Council (NERC). Under Presidential Directive 12, employee and contractor identities and suitability must be confirmed through background checks. "Everyone undergoes some form of identity verification and must display their identification badge when they are on the facility," Gregson said.The following slideshow shows various areas, from the road over the dam to the surrounding buildings and tunnels within the dam itself, as well as the energy-producing machinery and surrounding work spaces, a small representation of the diverse spaces that the Hoover Dam Police Department and security staff protect.