Founded in 1956, the National Radio Astronomy Observatory is a federally funded U.S. research center for radio astronomy, supported by the National Science Foundation and operated by Associated Universities, Inc. It functions as a network of facilities rather than a single site, with major operations in Charlottesville, Socorro, Chile, Tucson, and especially Green Bank, West Virginia. Its instruments have included the Very Large Array, the Very Long Baseline Array, ALMA participation, and the Green Bank Telescope. Green Bank is also notable for the National Radio Quiet Zone, which restricts interference, and for the collapse of its 300-foot telescope in 1988, followed by construction of a replacement.