One Square Inch of Silence is a noise control project symbolized by a small red stone symbolically placed in Hoh Rainforest at Olympic National Park in 2005 by author and sound recording specialist Gordon Hempton. The stone's location has been called "the quietest place in the United States". According to commercial pilot Philip Greenspun, some airlines have voluntarily rerouted flights to avoid inducing noise pollution at the square inch. Hempton has formed a foundation to prevent jet aircraft noise in Olympic National Park and other parks.