of non-natives. In particular, the west coast of the United States showed the most dramatic change, beginning with the California Gold Rush and the subsequent opening of the transcontinental railroads, through the development of Hollywood in Southern California, and increased industry and agriculture in the U.S. Pacific Northwest. Canadian and Mexican development also proceeded during this time, but at a slower pace. United States Americans in California rebelled against Mexico, and in 1846 established the short-lived California Republic. However, the Mexican–American War had already been declared, and the American military quickly took control of California. At the end of the war, Mexico ceded control of California to the United States. Things began to change dramatically in 1848 with the California Gold Rush which brought an influx of migrants across the nation and immigrants from around the world. While few found much gold, many stayed, founding communities and turning to farming and other practices. Despite these increases in population, the west coast was still on the periphery. The American Civil War had little effect, but began to change as the first transcontinental railroads (completed in 1869) stretched across the United States. For the first time, it was relatively cheap and easy for migrants and immigrants to move to the west coast. In 1867, the United States acquired Alaska from the Russian Empire, capping American westward expansion on the North American continent. The next 75 years saw a monumental change on the west coast of the United States. Successive booms of agriculture, oil, entertainment, and industry greatly increased California's population. Logging, fishing, and industry drove the economies of California, Oregon, and Washington. However, Alaska had a small economy, despite the three gold rush eras (Klondike, Nome, and Fairbanks) and commercial fishing. This was due to high costs and a risky investment climate that limited development in the Alaskan landscape. During World War II, defense companies like Boeing, Douglas Aircraft Company, Kaiser Shipyards, and Vigor Shipyards dominated the wartime manufacturing in the West Coast, especially in cities like Seattle, Portland, and Los Angeles. Military investment into Alaska also increased in response to the growing threat from Imperial Japan in the Pacific War. Hoping to bring the conflict further into the continental U.S., Japan launched a series of attacks by land, air, and sea on the Pacific Coast as part of the American Theater, such as the Bombardment of Ellwood, the Aleutian Islands Campaign,