In the 1920s Henry Woodhouse proposed George Washington Air Junction, which would have been the world's largest airport. Under the original plan George Washington Air Junction would have featured three 7,500 foot long runways, dirigible tethers, and 1,500 to 2,000 acres of land in Hybla Valley, one of the flattest areas of land near Washington, DC. Although land was purchased for it in Fairfax County, Virginia, the proposal never came to fruition due to the onset of the Great Depression. In the 1930s Woodhouse was forced to sell the land to pay taxes, and in 1941 it was acquired by the United States federal government, which used it as an asphalt test center during the 1940s, an air defense site in the 1950s, and a radio research center between 1958 and 1971. In 1975 it was donated to the Fairfax County government to become Huntley Meadows Park. There are a number of different scenarios in which the Hybla Valley could be developed. In addition to the original plan being completed, George Washington Air Junction could also have been developed during the 1940s as a replacement for Hoover Field, an early airport outside Washington, DC, whose site was used for the Pentagon (Washington National Airport was the historical replacement). The larger facilities could have hosted airship operations and possibly have been used as a site for an aircraft factory. The site also could have been developed later on as an alternative to Washington Dulles International Airport (historically criticized as being too far from Washington, DC), or perhaps it could have expanded from its historical air defense and radio research role into a major air defense site for the capital (possibly as the United States capital site allowed under the Anti-Ballistic Missile Treaty. What might have happened if the George Washington Air Junction had been built? Could such large facilities have made Virginia and the Washington, DC, area a major aviation hub? Would the site have been suitable for Cold War air defense operations?