San Francisco 1

The 1989 Loma Prieta earthquake caused destruction and loss of life throughout the Bay Area. In San Francisco, the quake severely damaged structures in the Marina and South of Market districts and precipitated the demolition of the damaged Embarcadero Freeway and much of the damaged Central Freeway, allowing the city to reclaim its historic downtown waterfront. During the dot-com boom of the late 1990s, startup companies invigorated the economy. Large numbers of entrepreneurs and computer application developers moved into the city, followed by marketing and sales professionals, changing the social landscape as once-poorer neighborhoods became gentrified. When the bubble burst in 2001, many of these companies folded, and their employees left, although high technology and entrepreneurship continue to be mainstays of the San Francisco economy.

San Francisco is located on the West Coast of the United States at the north-facing tip of the San Francisco Peninsula and includes significant stretches of the Pacific Ocean and San Francisco Bay within its boundaries. Several islands (Alcatraz, Treasure Island, and the adjacent Yerba Buena Island, and a small portion of Alameda Island, Red Rock Island, and Angel Island are part of the city). Also included are the uninhabited Farallon Islands, 27 miles (43?km) offshore in the Pacific Ocean. The mainland within the city limits roughly forms a "seven-by-seven-mile square," a common local colloquialism referring to the city's shape, though its total area, including water, is nearly 232 square miles (600?km2).

San Francisco is famous for its hills. There are more than 50 hills within city limits.[52] Some neighborhoods are named after the hill on which they are situated, including Nob Hill, Pacific Heights, and Russian Hill. Near the geographic center of the city, southwest of the downtown area, are a series of less densely populated hills. Twin Peaks, a pair of hills resting at one of the city's highest points, forms a popular overlook spot. San Francisco's tallest hill, Mount Davidson, is 925 feet (282 m) high and is capped with a 103-foot (31?m) tall cross built in 1934.[53] Dominating this area is Sutro Tower, a large red and white radio and television transmission tower.

The nearby San Andreas and Hayward Faults are responsible for much earthquake activity, although neither physically passes through the city itself. The San Andreas Fault caused the earthquakes in 1906 and 1989. Minor earthquakes occur on a regular basis. The threat of major earthquakes plays a large role in the city's infrastructure development. The city has repeatedly upgraded its building codes, requiring retrofits for older buildings and higher engineering standards for new construction. However, there are still thousands of smaller buildings that remain vulnerable to quake damage.

San Francisco's shoreline has grown beyond its natural limits. Entire neighborhoods such as the Marina and Hunters Point, as well as large sections of the Embarcadero, sit on areas of landfill. Treasure Island was constructed from material dredged from the bay as well as material resulting from tunneling through Yerba Buena Island during the construction of the Bay Bridge. Such land tends to be unstable during earthquakes; the resultant liquefaction causes extensive damage to property built upon it, as was evidenced in the Marina district during the 1989 Loma Prieta earthquake.

A popular quote incorrectly attributed to Mark Twain is "The coldest winter I ever spent was a summer in San Francisco."[57][58] San Francisco's climate is characteristic of the cool-summer Mediterranean climate[59] of California?s coast, "generally characterized by moist mild winters and dry summers."[60] Since it is surrounded on three sides by water, San Francisco's weather is strongly influenced by the cool currents of the Pacific Ocean, which moderates temperature swings and produces a remarkably mild year-round climate with little seasonal temperature variation.

Among major U.S. cities, San Francisco has the coldest daily mean, maximum, and minimum temperatures for June, July and August. During the summer, rising hot air in California's interior valleys creates a low pressure area that draws winds from the North Pacific High through the Golden Gate, which creates the city's characteristic cool winds and fog. The fog is less pronounced in eastern neighborhoods and during the late summer and early fall, which is the warmest time of the year. Because of its sharp topography and maritime influences, San Francisco exhibits a multitude of distinct microclimates. The high hills in the geographic center of the city are responsible for a 20% variance in annual rainfall between different parts of the city. They also protect neighborhoods directly to their east from the foggy and sometimes very cold and windy conditions experienced in the Sunset District; for those who live on the eastern side of the city, San Francisco is sunnier, with an average of 260 clear days, and only 105 cloudy days per year.

Temperatures exceed 75 F on average only 28 days a year.[63] The dry period of May to October is mild to warm, with average high temperatures of 64?71 ?F (18?22??C) and lows of 51?56 ?F (11?13??C). The rainy period of November to April is slightly cooler with high temperatures of 58?64 ?F (14?18??C) and lows of 46?51 ?F (8?11??C). On average, there are 67 rainy days a year, and annual precipitation averages 20.4 inches (518.16?mm).[63] Snow is extraordinarily rare, with only 10 instances recorded since 1852, most recently in 1976. The highest recorded temperature at the official National Weather Service office was 103 ?F (39??C) on July 17, 1988, and June 14, 2000. The lowest recorded temperature was 27 ?F (-3??C) on December 11, 1932. The U.S. National Weather Service provides a helpful visual aid[66] graphing the information in the table below to display visually by month the annual typical temperatures, the past year's temperatures, and record temperatures.

The historic center of San Francisco is the northeast quadrant of the city bordered by Market Street to the south. It is here that the Financial District is centered, with Union Square, the principal shopping and hotel district, nearby. Cable cars carry riders up steep inclines to the summit of Nob Hill, once the home of the city's business tycoons, and down to Fisherman's Wharf, a tourist area featuring Dungeness crab from a still-active fishing industry. Also in this quadrant are Russian Hill, a residential neighborhood with the famously crooked Lombard Street, North Beach, the city's Little Italy, and Telegraph Hill, which features Coit Tower. Nearby is San Francisco's Chinatown, established in the 1840s.

The Mission District was populated in the 19th century by Californios and working-class immigrants from Germany, Ireland, Italy and Scandinavia. In the 1910s, a wave of Central American immigrants settled in the Mission and, in the 1950s, immigrants from Mexico began to predominate.[74] In recent years rapid gentrification has spread, primarily along the Valencia Street corridor, which is strongly associated with modern hipster sub-culture. Haight-Ashbury, famously associated with 1960s hippie culture, later became home to expensive boutiques[75] and a few controversial chain stores,[76] although it still retains some bohemian character. Historically known as Eureka Valley, the area now popularly called the Castro is the center of gay life in the city.

The city's Japantown district suffered when its Japanese American residents were forcibly removed and interned during World War II. The nearby Western Addition became established with a large African American population at the same time. The "Painted Ladies", a row of well-restored Victorian homes, stand alongside Alamo Square, and the mansions built by the San Francisco business elite in the wake of the 1906 earthquake can be found in Pacific Heights. The Marina to the north is a lively area with many young urban professionals. The Richmond, the vast region north of Golden Gate Park that extends to the Pacific Ocean, has a portion called "New Chinatown" but is also home to immigrants from other parts of Asia and Russia. South of Golden Gate Park lies the Sunset with a predominantly Asian population.[79] The Richmond and the Sunset are largely middle class and, together, are known as The Avenues. These two districts are each sometimes further divided into two regions: the Outer Richmond and Outer Sunset can refer to the more Western portions of their respective district and the Inner Richmond and Inner Sunset can refer to the more Eastern portions. Bayview-Hunters Point in the southeast section of the city is one of the poorest neighborhoods and suffers from a high rate of crime, though the area has been the focus of controversial plans for urban renewal. The South of Market, once filled with decaying remnants of San Francisco's industrial past, has seen significant redevelopment. The locus of the dot-com boom during the late 1990s, by 2004 South of Market began to see skyscrapers and condominiums dot the area (see Manhattanization). Following the success of nearby South Beach, another neighborhood, Mission Bay, underwent redevelopment, anchored by a second campus of the University of California, San Francisco. Just southwest of Mission Bay is the Potrero Hill neighborhood featuring sweeping views of downtown San Francisco.