California (pronounced /kælɨˈfɔrnjə/ ( listen)) is the most populous[4] state in the United States, and the third largest by area. California is the second most populous sub-national entity in the Americas, behind only São Paulo, Brazil. It is located on the West Coast of the United States, and is bordered by Oregon to the north, Nevada to the northeast, Arizona to the southeast, the Mexican state of Baja California to the south, and the Pacific Ocean to the west. Its four largest cities are Los Angeles, San Diego, San Jose, and San Francisco.[5] The state is home to the nation's second and sixth largest metropolitan areas as well as eight of the nation's fifty largest cities. California has varied climate and geography and a diverse population. California is the third-largest U.S. state by land area, after Alaska and Texas. Its geography ranges from the Pacific coast to the Sierra Nevada mountain range in the east, to Mojave desert areas in the southeast and the Redwood–Douglas fir forests of the northwest. The center of the state is dominated by the Central Valley, one of the most productive agricultural areas in the world. California is the most geographically diverse state in the nation, and contains the highest (Mount Whitney) and lowest (Death Valley) points in the contiguous United States. Beginning in the late 18th century, the area known as Alta California was colonized by the Spanish Empire. In 1821, Mexico, including Alta California, became an independent republic. In 1846 a group of American settlers in Sonoma declared the independence of a California Republic. As a result of the Mexican-American War, Mexico ceded California to the United States. It became the 31st state admitted to the union on September 9, 1850. In the 19th century, the California Gold Rush brought about dramatic social, economic, and demographic change in California, with a large influx of people and an economic boom that caused San Francisco to grow from a hamlet of tents to a world-renowned boomtown. Key developments in the early 20th century included the emergence of Los Angeles as center of the American entertainment industry, and the growth of a large, state-wide tourism sector. In addition to California's prosperous agricultural industry, other important contributors to the economy include aerospace, petroleum, and information technology. If California were a country, it would rank among the ten largest economies in the world, with a GDP similar to that of Italy. It would be the 35th most populous country. The word California originally referred to the entire region composed of what is today the state of California, plus all or parts of Nevada, Utah, Arizona, and Wyoming, and the Mexican peninsula of Baja California. The name California is most commonly believed to have derived from a fictional paradise peopled by Black Amazons and ruled by a Queen Califia. The myth of Califia is recorded in a 1510 work The Exploits of Esplandian, written as a sequel to Amadís de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo.[6] The kingdom of Queen Califia or Calafia, according to Montalvo, was said to be a remote land inhabited by griffins and other strange beasts and rich in gold. Know ye that at the right hand of the Indies there is an island named California, very close to that part of the terrestrial Paradise, which was inhabited by black women, without a single man among them, and that they lived in the manner of Amazons. They were robust of body, with strong and passionate hearts and great virtues. The island itself is one of the wildest in the world on account of the bold and craggy rocks. Their weapons were all made of gold. The island everywhere abounds with gold and precious stones, and upon it no other metal was found.[7] The name California is the fifth-oldest surviving European place-name in the U.S. and was applied to what is now the southern tip of Baja California as the island of California by a Spanish expedition led by Diego de Becerra and Fortun Ximenez, who landed there in 1533 at the behest of Hernando Cortes.[8] California adjoins the Pacific Ocean, Oregon, Nevada, Arizona, and the Mexican state of Baja California. With an area of 160,000 square miles (414,000 km2), it is the third-largest state in the United States in size, after Alaska and Texas.[9] If it were a country, California would be the 59th-largest in the world in area. In the middle of the state lies the California Central Valley, bounded by the coastal mountain ranges in the west, the Sierra Nevada to the east, the Cascade Range in the north and the Tehachapi Mountains in the south. The Central Valley is California's agricultural heartland and grows approximately one-third of the nation's food.[10] Divided in two by the Sacramento-San Joaquin River Delta, the northern portion, the Sacramento Valley serves as the watershed of the Sacramento River, while the southern portion, the San Joaquin Valley is the watershed for the San Joaquin River; both areas derive their names from the rivers that transit them. With dredging, the Sacramento and the San Joaquin Rivers have remained sufficiently deep that several inland cities are seaports. The Sacramento-San Joaquin River Delta serves as a critical water supply hub for the state. Water is routed through an extensive network of canals and pumps out of the delta, that traverse nearly the length of the state, including the Central Valley Project and the State Water Project. Water from the Delta provides drinking water for nearly 23 million people, almost two-thirds of the state's population, and provides water to farmers on the west side of the San Joaquin Valley. The Channel Islands are located off the southern coast. The Sierra Nevada (Spanish for "snowy range") includes the highest peak in the contiguous forty-eight states, Mount Whitney, at 14,505 ft (4,421 m).[3] The range embraces Yosemite Valley, famous for its glacially carved domes, and Sequoia National Park, home to the giant sequoia trees, the largest living organisms on Earth, and the deep freshwater lake, Lake Tahoe, the largest lake in the state by volume. To the east of the Sierra Nevada are Owens Valley and Mono Lake, an essential migratory bird habitat. In the western part of the state is Clear Lake, the largest freshwater lake by area entirely in California. Though Lake Tahoe is larger, it is divided by the California/Nevada border. The Sierra Nevada falls to Arctic temperatures in winter and has several dozen small glaciers, including Palisade Glacier, the southernmost glacier in the United States. About 45 percent of the state's total surface area is covered by forests, and California's diversity of pine species is unmatched by any other state. California contains more forestland than any other state except Alaska. Many of the trees in the California White Mountains are the oldest in the world; one Bristlecone pine has an age of 4,700 years. In the south is a large inland salt lake, the Salton Sea. Deserts in California make up about 25 percent of the total surface area. The south-central desert is called the Mojave; to the northeast of the Mojave lies Death Valley, which contains the lowest, hottest point in North America, Badwater Flat. The distance from the lowest point of Death Valley to the peak of Mount Whitney is less than 200 miles (322 km). Indeed, almost all of southeastern California is arid, hot desert, with routine extreme high temperatures during the summer. Along the California coast are several major metropolitan areas, including Greater Los Angeles, the San Francisco Bay Area, and San Diego. California is famous for earthquakes due to a number of faults, in particular the San Andreas Fault. It is vulnerable to tsunamis, floods, droughts, Santa Ana winds, wildfires, landslides on steep terrain, and has several volcanoes. California climate varies from Mediterranean to subarctic. Much of the state has a Mediterranean climate, with cool, rainy winters and dry summers. The cool California Current offshore often creates summer fog near the coast. Further inland, one encounters colder winters and hotter summers. Northern parts of the state average higher annual rainfall than the south. California's mountain ranges influence the climate as well: some of the rainiest parts of the state are west-facing mountain slopes. Northwestern California has a temperate climate, and the Central Valley has a Mediterranean climate but with greater temperature extremes than the coast. The high mountains, including the Sierra Nevada, have a mountain climate with snow in winter and mild to moderate heat in summer. The east side of California's mountains produce a rain shadow, creating expansive deserts. The higher elevation deserts of eastern California see hot summers and cold winters, while the low deserts east of the southern California mountains experience hot summers and nearly frostless mild winters. Death Valley, a desert with large expanses below sea level, is considered the hottest location in North America; the highest temperature in the Western Hemisphere, 134 °F (57 °C), was recorded there on July 10, 1913. California is one of the richest and most diverse parts of the world, and includes some of the most endangered ecological communities. California is part of the Nearctic ecozone and spans a number of terrestrial ecoregions. California's large number of endemic species includes relict species, which have died out elsewhere, such as the Catalina Ironwood (Lyonothamnus floribundus). Many other endemics originated through differentiation or adaptive radiation, whereby multiple species develop from a common ancestor to take advantage of diverse ecological conditions such as the California lilac (Ceanothus). Many California endemics have become endangered, as urbanization, logging, overgrazing, and the introduction of exotic species have encroached on their habitat. California boasts several superlatives in its collection of flora: the largest trees, the tallest trees, and the oldest trees. California's native grasses are perennial plants.[11][12] After European contact, these were generally replaced by invasive species of European annual grasses; and, in modern times, California's hills turn a characteristic golden-brown in summer.