For thousands of years, Native Americans called the Ohlone managed and harvested the natural bounty of what is now the Presidio. In 1776, Spanish soldiers and missionaries arrived, forever disrupting Ohlone culture and beginning 218 years of military use of the area just south of the Golden Gate. The Presidio served as a military post under the flags of Spain (1776-1822), Mexico (1822-48), and the United States (1848-1994). As a U.S. Army post, the Presidio protected commerce and trade, and played a logistical role in every major U.S. military conflict over the last 150 years. World events and those on the home front - from military campaigns to the rise of aviation, from World Fairs to natural disasters - left their mark here. On October 1, 1994, the Presidio became part of the Golden Gate National Recreation Area. Since 1998, the Presidio has been jointly managed by the National Park Service and the Presidio Trust. The Presidio Trust is a special public-private governmental agency tasked with managing most of the buildings of the Presidio and making the park financially self-sufficient by 2013. Today, visitors can enjoy the history and beauty of the Presidio. Within its 1,480 acres are more than 500 historic buildings, a collection of coastal defense fortifications, a national cemetery, an historic airfield, a saltwater marsh, forests, beaches, native plant habitats, coastal bluffs, miles of hiking and biking, and some of the most spectacular vistas in the world.