Started in World War II in Washington, D.C., the Air Force Historical Research Agency (AFHRA) has the largest collection of US military aviation documents, with more than 70,000,000 pages all told within their holdings. Since 1949, it has been housed at Maxwell Air Force Base in Alabama, and is open to the general public, military students, researchers, and scholars. Visitors will find some interesting reading under the Studies tab, which includes "Numbered USAF Historical Studies", some of which are designated Secret, and others Unclassified. Also interesting are the "Short Studies on Recent Operations" available in PDF, and including such topics as "Weather in Air Campaigns, 1990-2003" and "The U.S. Air Force Response to Hurricane Katrina". Nearby, under "Other Studies", visitors will find "A Study of Females on Minuteman/Peacekeeper Crews, 31 January 1985" and "Chronology: 100 Years of Flight".