San Francisco was incorporated in 1850, when there was just one communal outdoor space: Portsmouth Square. The square was the literal nucleus of planning for the city, as development maps were measured from its center point. Over time, the city developed into the current metropolis with a population of around 815,000. In a reflection of that growth, 230 parks are now governed and maintained by the San Francisco Recreation and Park Department. The variety of spaces administered by the department includes parks, playgrounds, miniparks, open spaces, and community gardens--within these, many different activities and programs are on offer. In 2017, San Francisco was cited as the nation's first city where every resident lives within a 10-minute walk to a park; this was calculated by the Trust for Public Land, a national nonprofit that facilitates the creation of parks and analyzes parks for the nation's 100 largest cities.