Walking tour of Fort Mason. Fort Mason is a complex of renovated military buildings that is home to many non profit organizations including the Mexican Museum and Greens Restaurant. It is part of The Golden Gate National Parks that include 75,500 acres of land and water taht extend north of the Golden Gate Bridge to Tomales Bay in Marin County and south to San Mateo County. Muir Woods National Monument, Crissy Field, the Presidio of San Francisco and Alcatraz are part of the park. With 19 unique ecosystems in seven distinct watersheds, five National Historic Landmarks and 61 archeological sites the parks perserve a wealth of natural and historic treasures.