sentences:  Due to its large, flat, grassy landscape, the site was turned into an airfield and became the home of significant aviation research and development between World War I and II.The site also housed a top-secret Military Intelligence Service Language School.When the military left after the war, it fell into relative disrepair until the National Park Service and Parks Conservancy oversaw its $34 million restoration, completed in 2001, which included a 28-acre re-creation airfield, as a part of the efforts to reinvigorate the Presidio as a national park.