Stroll along the Mission's wide avenues and you'll be struck by the profusion of taquerias, pupuserias, produce markets, Salvadoran bakeries, salon de bellezas (beauty salons), auto-repair shops and check-cashing centers that post rates for wiring money to Guatemala and Nicaragua -- all evidence of the Central American and Mexican families that have been settling the Mission en masse since the 1950s.
You'll also notice plenty of cafés, thrift shops and used-book stores that cater to the college grads, artists, activists and other alterna-types that until recently have been drawn to the Mission for its cheap rents. Note that "until recently," because with the Internet boom, even the Mission rents have shot up. Latinos and bohemians have been increasingly displaced by San Francisco's influx of highly paid young professionals, while trendy restaurants and boutiques have sprung up in what used to be the neighborhood's darkest corners.
The Mission has always been home to different ethnic and socioeconomic groups. The area was originally inhabited by a tribe called the Ramaytush that died of smallpox and various other ailments when the Spanish settlers corraled them into the rancherias surrounding Mission Dolores (established in 1776). After the missionaries came brawling Yankee squatters in the 1840s, a wave of German and Scandinavian immigrants in the 1860s and rich local merchants who built the Victorian mansions on South Van Ness and Liberty Hill in the 1870s (right before Pacific Heights became the place for the rich to live.)
After the 1906 quake destroyed several blue-collar neighborhoods, Irish and Italians relocated to the quickly expanding Mission. The neighborhood was far enough from downtown and becoming populous enough to support a large number of stores, restaurants and bars. In the early years of the 20th century, Mission residents developed a distinctive accent that allegedly sounded much like Brooklyn's.
Since the turn of the century there's been a steady trickle of Central American immigrants to the Mission, in part because of San Francisco's trade links with Central America. Since the 1950s, the Latino population in the Mission has doubled every 10 years, lending the neighborhood much of its current flavor.
The Mission is large, and it's crawling with things to see and do. We've broken it down into four areas. While the flavor of the neighborhood changes subtly from block to block, bear in mind that these areas are contiguous and you can easily walk from one to the other. Generally speaking, the 24th Street area is the culturally rich heart of the Mission, the stretch from Dolores Street through to Valencia Street is young and upscale, the area around 16th and Valencia streets hops with nightlife and the industrial area near Bryant Street is full of hip, trendy new restaurants.