El Polín Spring
When the Spanish established Mission Dolores and the Presidio (fort) in 1776, they relied on freshwater springs to supply their settlement. One of these, El Polín Spring, is the site of one of the Presidio's first non-military settlements and the home of the extended Briones family from 1810-1850. Archaeological excavations between 2003 and 2015 revealed the green Serpentine stone foundation of an adobe house belonging to Marcos Briones, early nineteenth century terra-cotta roof tiles, a kiln, and refuse deposits, as well as landform modification associated with the Briones family. Both colonial and Native American artifacts have been found at the site, the former represented by both imported and local ceramics, glass container fragments, and metal, and the latter represented by worked shell and stone. During and following the archaeological investigations at El Polín Spring, the Presidio Trust worked to restore the area's habitat, which soil studies had shown to vary between marshes, small streams, sand dunes, and hills. A series of small ponds and sunken spillways are now interspersed with wetlands, and the area is a hot spot for bird watching.
Inn at the Presidio, Pershing Hall (Former Bachelor Officer's Quarters)
Built by the U. S. Army as quarters for unmarried officers in 1903, the Georgian Revival-style Pershing Hall was named for General John J. "Blackjack" Pershing (1886-1924), who served at the Presidio of San Francisco beginning in 1913. As a fire precaution, Pershing Hall was constructed as three separate wings, and later served as Visiting Officers' Quarters until the Army turned the Presidio over to the National Park Service in 1994. Now, the building is listed on the National Register of Historic Places and National Historic Landmarks and has been converted into an inn, each wing of which is named for a general who once lived in the building.
Tides Thoreau Center San Francisco
The original (1898-1902) U. S. Army (Letterman) General Hospital building (a National Historic Landmark), along with eleven other Presidio buildings, house the Thoreau Center for Sustainability. The Center's renovation of the hospital buildings began in 1995, and combined historic preservation with green building principles. The Thoreau Center houses over 60 non-profit organizations in 150,000 square feet, as well as the Whole Earth Library, two art galleries, and a cafe. Some of the Center's tenants include the World Wildlife Fund, Art Seed, Bay Area Ridge Trail Council, Community Clinics Initiative, Door Dog Music Productions, Friends of the Urban Forest, Lawyers for Clean Water, and the Northern California Independent Booksellers. The free-admission China Brotsky Art Gallery, named after the Tides senior vice president, is housed in one of the Letterman Hospital windowed corridors and is dedicated to environmentally-themed works.