Many of the main factors that shaped Anchorage were geographic circumstance. The first was prehistoric: the various openings of the Bering Land Bridge, starting about 30,000 years ago, that brought humans to North America, including the Tanaina people who inhabited Cook Inlet before European contact. The area was largely ignored during initial Russian colonization of Alaska; nor did the 1867 purchase of Alaska by the U.S. bring Cook Inlet any importance. Happenstance made it the 1914 location for a port during construction of the Alaska Railroad. The resulting tent city along Ship Creek gave way to more formal development, and Anchorage was incorporated in 1920. World War II brought two huge military bases, Fort Richardson and Elmendorf Air Force Base, both still major players in the economy. The devastating 1964 Good Friday earthquake, strongest ever in North America, brought a spate of rebuilding largely responsible for the city’s mid-century architectural appearance (drabness, many would say). And the 1970s construction of the Alaska Pipeline brought thousands of workers and millions of dollars in oil money to town; both remain, and oil company office towers are the most conspicuous structures in the city. Anchorage is also one of the world’s main international air hubs—for cargo planes carrying goods between Asia and Europe. These behemoth craft, mostly 747s, set down here in an almost unbroken stream so they can take on fuel to continue their long intercontinental journeys. This makes the city’s airport the world’s third-busiest for cargo traffic, a geographic accident derived from its midway location along the great circle routes between Europe and Asia, and transportation remains a key economic driver.