The U.S. Census records 319,198 people in the City of Los Angeles and 504,131 people for all Los Angeles County. The first international Air Meet ever is held at Dominguez Field for ten days. The first powered flight in the west occurs at this event. A bomb explosion, resulting in the death of 21 people, destroys the printing plant of the Los Angeles Times. Harrison Otis of the Los Angeles Times unites with Los Angeles business interests to fight the activities of trade unions. Hollywood is annexed by the City of Los Angeles in order to receive water from the city’s new water supply. The 11,050-foot breakwater at Los Angeles Harbor is completed. Los Angeles counts 7,599 African-American residents, the largest African-American urban population in the Western United States.
Union leaders James and Joseph McNamara are convicted of the Los Angeles Times bombing. Clarence Darrow, their defense attorney, is indicted for bribing the jury but is later acquitted. African Americans are barred from beaches in Manhattan Beach. C.P. Rodgers makes the first transcontinental airplane flight from New York to Pasadena. He makes numerous stops along the way and spends 82 hours and 4 minutes in the air. Bessie Bruington Burke becomes the first African-American to teach in Los Angeles public schools. She later goes on to become the city's first African-American school principal. The first permanent film studio in Hollywood is set up by the Nestor Motion Picture Company in the Bandeau Tavern Building at the northwest corner of Sunset Boulevard and Gower Street.
The African-American-owned Golden West Hotel is erected on Central Avenue. The first gas station in Los Angeles opens. The Museum of History, Science and Art opens. The Los Angeles County Library is established.
The Los Angeles Aqueduct begins delivering water from the Owens Valley. It was the largest municipal water system in the nation and transformed the San Fernando Valley. The California legislature passes the Alien Land Bill that limits leases and purchases of agricultural land to Japanese persons. Cecil B. DeMille telegrams his New York partners for authority to rent a barn in Hollywood to film the motion picture The Squaw Man. The Southwest Museum opens. Over Los Angeles, Georgia Broadwick becomes the first women to parachute from an airplane. California's first branch of the NAACP is established in Los Angeles.
Heavy flooding causes $10 million in damage, including tremendous damage to the Los Angeles Harbor. With the commercial success of the film The Birth of a Nation by D.W. Griffith (despite its blatantly negative portrayal of African Americans and positive portrayal of the Ku Klux Klan), Los Angeles becomes the center of the motion picture industry. Ford Motor Company opens the first auto assembly plant in Southern California in Los Angeles at Seventh and Santa Fe Streets to assemble Model T Fords. The S.S. Missourian becomes the first vessel to dock at Los Angeles Harbor after passing through the Panama Canal.
Prompted by severe flooding from the year before, the Los Angeles County Flood Control District is formed. The San Fernando Valley is annexed by the City of Los Angeles. Direct steamer service is established between Los Angeles and Japan.
Upton Sinclair settles in Pasadena. Donald Douglas founds his own aviation company. A large number of African-Americans from the south migrate to Los Angeles. The first overhead power lines in Los Angeles are strung by the Bureau of Power and Light. Captain G. Allan Hancock donates Hancock Park, which includes La Brea Tar Pits, to the county.
The Tournament of Roses switches back to football games from chariot games. Architect Frank Lloyd Wright begins building the "Hollyhock House" for heiress Aline Barnsdall, the first of five houses in the Los Angeles area. For the first time, the population of Los Angeles exceeds that of San Francisco. Forest Lawn Cemetery is established in Glendale.
A 100-inch telescope is installed in the Mount Wilson Observatory. The Second Street Tunnel beneath Bunker Hill opens.
Shell Oil begins oil exploration in Long Beach on Signal Hill. A former Indian campsite is selected to be the future Hollywood Bowl site. The Los Angeles Philharmonic Orchestra is founded. The University of California, Southern Branch (UCLA), is formed from the State Normal School. William Wrigley Jr. and several other investors purchase Catalina Island from the Banning family. The island is then developed and promoted for tourism. After more than a decade of failed efforts to unionize and improve workplace policies, frustrated Pacific Electric Railway workers respond to a denial to unionize by the National War Labor Board with violent protests and a strike. Police are called out to subdue the strikers. Workers ultimately receive a pay raise but the open shop policy continues.
The U.S. Census records 576,673 people in the City of Los Angeles and 936,455 people for all Los Angeles County. Despite comedian Roscoe "Fatty" Arbuckle's clear acquittal of charges of sexually assault and manslaughter of aspiring actres Virginia Rappe at a San Francisco party, outcries against Hollywood morality leads the movie industry to try changing its product and image. The Los Angeles Metropolitan Water District takes its water search to the Colorado River. A large migration of Mexicans to Los Angeles begins. Southern California passes up Northern California in population.
Simon Rodia, an unemployed Italian immigrant welder, begins 33 years of work on what would become known as the Watts Towers. It is a tribute to his adopted homeland. The Union Oil Company discovers oil on the Alphonzo Bell Ranch in Santa Fe Springs. Amelia Earhart Putnam's flying career begins in Los Angeles when, at age 24, she takes flying lessons from Neta Snook and buys her first airplane.
A.W. Ross establishes Wilshire Boulevard as a "shopping" district. The Port of Los Angeles is selected as the base of the U.S. Navy Pacific Fleet. The Rose Bowl is completed. The Hollywood Bowl opens with its first performance and hosts its first Easter sunrise service. Radio broadcasting comes to Los Angeles with stations KHJ, KFI and KNX. "Reb" Spikes recorded the Kid Ory band in a Central Avenue studio, the first audio recording of an African American New Orleans jazz band.
Angelus Temple is established. One of the largest churches in the nation, it serves as the home of Aimee Semple McPherson, a flamboyant and charismatic faith healer and preacher. McPherson becomes one of the most talked about Los Angeles personalities in the 1920s. The Los Angeles Memorial Coliseum is completed. The Hollywoodland sign is erected.
The first dynamite blast occurs on the Los Angeles Aqueduct as Owens Valley residents attempt to block further diversion of the Owens River to Los Angeles. A small army of Owens Valley residents seizes the Los Angeles Aqueduct near Lone Pine and shuts off the water flow to Los Angeles. Los Angeles City’s population reaches one million. Of these, 43,000 are real estate agents. An opera company is established in Los Angeles. The first airplane to ever fly around the world is built in Santa Monica. It is a Douglas World Cruiser named New Orleans.
The main Public Library Building is completed in downtown Los Angeles. Due to overcrowding at the Vermont Avenue campus of the University of California in Los Angeles, voters in Los Angeles, Beverly Hills, Santa Monica and Venice (then an independent city) approve $1 million in bonds for the purchase of a Westwood site for a new campus. Work begins on a new subway and the Subway Terminal Building on Hill Street. The new Shrine Auditorium opens (replacing the former structure that had been destroyed by fire). Patriotic Hall and Olympic Auditorium are completed. Airmail service begins in Los Angeles. Miss Aline Barnsdall presents her property on Olive Hill as an art center and park. The Sears-Roebuck Building on East Ninth Street opens.
Aimee McPherson disappears while swimming near Ocean Park, only to reappear a week later in a Mexican border town. The Spanish language newspaper La Opinion is first published. The new Los Angeles Central Library opens.
Los Angeles deploys a trainload of World War I veterans to the Owens Valley to patrol the Los Angeles Aqueduct. The first Los Angeles Open golf tournament is held. Warner Brothers ends the silent era of movies with their "talkie" The Jazz Singer. The first movie premier opens at Grauman’s Chinese Theater. It was the first time klieg lights were used for a promotion. A throng of 200,000 greets aviator Charles Lindbergh and his Spirit of St. Louis, upon visiting Los Angeles.
Los Angeles is found to have the highest suicide rate in the nation. The San Francisquito Dam bursts, tragically taking 400 lives in the resulting flood. The new Los Angeles city hall is opened. A daily air link between Los Angeles and San Francisco opens for passengers. The Metropolitan Water District of Southern California is established by charter cities Beverly Hills, Burbank, Compton, Fullerton, Glendale, Long Beach, Los Angeles, Pasadena, San Marino, Santa Monica, Torrance, Anaheim and Santa Ana. The Hotel Sommerville (renamed Dunbar Hotel in 1929), a popular center for African Americans, is opened on Central Avenue by Dr. John Sommerville (who, with wife Vada Watson, were the first African Americans to graduate from the USC School of Dentistry). The hotel hosts the first national convention of the NAACP in the west. Christine Sterling begins the restoration of Olvera Street. The Henry E. Huntington Library opens to the public. The first Mickey Mouse cartoon is made. The Los Angeles City Council selects 640 acres of a former wheat, barley, and lima bean field as the location for the new City of Los Angeles Airport. The property is first named Mines Field for real estate agent William W. Mines who arranges the deal. The airport is composed of dirt strips with no buildings.
Groundbreaking ceremonies are held for the new Pacific Stock Exchange. Wall Street and crashes one week later. The first motion picture Academy Awards are presented. UCLA moves to the Westwood location. The dirigible Graf Zeppelin lands at Mines Field after flying in from Japan. The Hotel Sommerville, a popular center for African Americans opened only the year before, is sold to Lucius Lomax Sr. The hotel is renamed Dunbar Hotel to honor poet Paul Laurence Dunbar.