Los Angeles is the largest city in the state of California by population and the second most populous city in the United States. Often abbreviated as L.A., it is an alpha world city having an estimated 2006 population of 3,849,378 and spanning 469.1 square miles (1,214.9 square kilometers). The Los Angeles–Long Beach–Santa Ana metropolitan area is the estimated home to nearly 13 million people. The Greater Los Angeles Area, encompassing a larger area of five counties, has an estimated population of over 17.7 million people. Los Angeles is the county seat of Los Angeles County and its inhabitants are referred to as "Angelenos."
Los Angeles was founded in 1781 by Spanish governor Felipe de Neve as El Pueblo de Nuestra Señora la Reina de los Ángeles de Porciúncula (The Village of Our Lady, the Queen of the Angels of Porciuncula). It became a part of Mexico in 1821 following independence from Spain and then a part of the United States in 1848 at the conclusion of the Mexican-American War. It was incorporated as a municipality on April 4, 1850—five months before California achieved statehood.
Los Angeles is one of the world's centers of culture, science, technology, international trade, and higher education, and is home to world-renowned institutions in a broad range of professional and cultural fields. The city and its immediate vicinity lead the world in producing popular entertainment—such as motion picture, television, and recorded music—which forms the base of Los Angeles' international fame and global status.
The Los Angeles coastal area was first settled by the Tongva (or Gabrieleños) and Chumash Native American tribes thousands of years ago. The first Europeans arrived in 1542 under Joao Cabrilho, a Portuguese explorer who claimed the area as the City of God for the Spanish Empire but continued with his voyage and did not establish a settlement. The next contact would not come until 227 years later when Gaspar de Portola, together with Franciscan missionary Juan Crespi, reached the present site of Los Angeles on August 2, 1769. Crespi noted that the site had the potential to be developed into a large settlement.
In 1771, Franciscan friar Junipero Serra had the Mission San Gabriel Arcangel built near Whittier Narrows in what is now called San Gabriel Valley. In 1777, the new governor of California, Felipe de Neve, recommended to the viceroy of New Spain that the site previously recommended by Juan Crespi be developed into a pueblo. The town was founded on September 4, 1781 by a group of 44 settlers and was named "El Pueblo de Nuestra Señora la Reina de los Ángeles del Río de Porciúncula," ("The Town of Our Lady the Queen of the Angels on the River Porciúncula"). These settlers were of Filipino, Native American, African, and Spanish ancestry, with two-thirds being mestizo or mulatto; a majority of the settlers had at least partial African ancestry. The settlement remained a small ranch town for decades, but by 1820 the population had increased to about 650 residents, making it the largest civilian (non-mission) community in Spanish California. Today, the pueblo is commemorated in the historic district Olvera Street, the oldest part of Los Angeles.
New Spain achieved its independence from the Spanish Empire in 1821, and the pueblo continued as a part of Mexico. Mexican rule ended during the Mexican-American War, when Americans took control from the Californios after a series of battles, culminating in the signing of the Treaty of Cahuenga on January 13, 1847. Later, with the Treaty of Guadalupe Hidalgo in 1848, the Mexican government formally ceded Alta California and other territories to the United States.
Railroads arrived when the Southern Pacific completed its line to Los Angeles in 1876. Oil was discovered in 1892, and by 1923 Los Angeles was producing one-quarter of the world's petroleum. By 1900, the population had grown to more than 100,000 people , which began to tax Los Angeles' water supply. The 1913 completion of the Los Angeles aqueduct under the supervision of William Mulholland assured the continued growth of the city. In 1915, Los Angeles began the annexation of dozens of neighboring communities without water supplies of their own.
In the 1920s, the motion picture and aviation industries flocked to Los Angeles, eventually becoming cornerstones of the local economy. In 1932, with population surpassing one million, hosted the Summer Olympics. This period also saw the arrival of exiles from the increasing pre-war tension in Europe, including Thomas Mann, Fritz Lang, Bertolt Brecht, Arnold Schoenberg, and Lion Feuchtwanger. World War II brought new growth and prosperity to the city, although many of its Japanese-American residents were transported to internment camps for the duration of the war. The post-war years saw an even greater boom as urban sprawl expanded the city into the San Fernando Valley.
Much like the rest of the United States, Los Angeles in the 1960s and early 1970s had to come to terms with changing race relations; the Watts riots in 1965, the high school walkout by Chicano students in 1968, and the 1970 Chicano Moratorium were representative of the racial strife present within the city. In 1969, Los Angeles became one of the birthplaces of the Internet, as the first ARPANET transmission was sent from UCLA to SRI in Menlo Park.
Los Angeles was the first city where AIDS was discovered in the 1980s and the center of many glam metal bands of the decade. In 1984, it hosted the Summer Olympics for the second time. The rest of the 1980s was plagued by an increase in gang violence, as crack cocaine became widely available. Racial tensions surfaced again in the 1990s with the Rodney King controversy and the large-scale riots that followed. In 1994, the Northridge earthquake shook the city, causing 72 deaths. Also that year, O.J. Simpson led police on a chase before surrendering to face murder charges in the deaths of his ex-wife and her friend. Despite propositions for the San Fernando Valley and Hollywood sections to secede from the city in 2002, residents voted down secession by a wide margin. The 2000s has seen a rise in urban redevelopment and gentrification in various parts of the city, most notably Echo Park and Downtown.
Los Angeles has a total area of 498.3 square miles (1,290.6 km²), comprising 469.1 square miles (1,214.9 km²) of land and 29.2 square miles (75.7 km²) of water. This makes it the 14th largest city in land area in the United States. The city extends for 44 miles (71 km) longitudinally and for 29 miles (47 km) latitudinally. The perimeter of the city is 342 miles (550 km).
The highest point in Los Angeles is Mount Lukens, also called Sister Elsie Peak. Located at the far reaches of the northeastern San Fernando Valley, it reaches a height of 5,080 ft (1,548 m). The major river is the Los Angeles River, which begins in the Canoga Park district of the city and is largely seasonal. The river is lined in concrete for almost its entire length as it flows through the city into nearby Vernon on its way to the Pacific Ocean.
The city is situated in a Mediterranean climate zone (Köppen climate classification Csb on the coast, Csa inland), experiencing mild, somewhat wet winters and warm to hot summers. Breezes from the Pacific Ocean tend to keep the beach communities of the Los Angeles area cooler in summer and warmer in winter than those further inland; summer temperatures can sometimes be as much as 18 °F (10 °C) warmer in the inland communities compared to that of the coastal communities. Coastal areas also see a phenomenon known as the "marine layer," a dense cloud cover caused by the proximity of the ocean that helps keep the temperatures cooler throughout the year. When the marine layer becomes more common and pervades farther inland during the months of May and June, it is called June Gloom.
Temperatures in the summer can get well over 90 °F (32 °C), but average summer daytime highs in downtown are 82 °F (27 °C), with overnight lows of 63 °F (17 °C). Winter daytime high temperatures will get up to around 65 °F (18 °C), on average, with overnight lows of 48 °F (10 °C) and during this season rain is common. The warmest month is August, followed by July and then September. This somewhat large case of seasonal lag is caused by Los Angeles' proximity to the ocean and its latitude of 34° north.
The median temperature in January is 57 °F (13 °C) and 73 °F (22 °C) in August. The highest temperature recorded within city borders was 119.0 °F (48.33 °C) in Woodland Hills on July 22, 2006; the lowest temperature recorded was 18.0 °F (−7.8 °C) in 1989, in Canoga Park. The highest temperature recorded for Downtown Los Angeles was 112.0 °F (44.4 °C) on June 26, 1990, and the lowest temperature recorded was 24.0 °F (−5.0 °C) on January 9, 1937.
Rain occurs mainly in the winter and spring months (February being the wettest month) with great annual variations in storm severity. Los Angeles averages 15 inches (38 cm) of precipitation per year. Snow is extraordinarily rare in the city basin, but the mountainous slopes within city limits typically receive snow every year. The greatest snowfall recorded in downtown Los Angeles was 2.0 inches (5 cm) on January 15, 1932.
The Los Angeles area is rich in native plant species due in part because of a diversity in habitats, including beaches, wetlands, and mountains. The most prevalent botanical environment is coastal sage scrub, which covers the hillsides in combustible chaparral. Native plants include: California poppy, matilija poppy, toyon, coast live oak, and giant wild rye grass. Many of these native species, such as the Los Angeles sunflower, have become so rare as to be considered endangered. Though it is not native to the area, the official flower of Los Angeles is Strelitzia reginae.
Due to geography, heavy reliance on automobiles, and the Los Angeles/Long Beach port complex, Los Angeles suffers from air pollution in the form of smog. The Los Angeles Basin and the San Fernando Valley are susceptible to atmospheric inversion, which holds in the fumes from road vehicles, airplanes, locomotives, shipping, manufacturing, and other sources. Unlike other large cities that rely on rain to clear smog, Los Angeles only gets 15 inches (381 mm) of rain each year, allowing pollution to accumulate over multiple consecutive days. This has brought much attention from the state of California to mandate low emissions vehicles. As a result, pollution levels have dropped in recent decades. The number of Stage 1 smog alerts has declined from over 100 per year in the 1970s to almost zero in the new millennium. Despite improvement, the 2006 annual report of the American Lung Association ranks the city as the most polluted in the country with short-term particle pollution and year-round particle pollution. In addition, the groundwater is increasingly threatened by MTBE from gas stations and perchlorate from rocket fuel. With pollution still a significant problem, the city continues to take steps to improve air and water conditions.