Depression of the 1930s, Omaha rebounded with the development of Offutt Air Force Base just south of the city. The Glenn L. Martin Company operated a factory there in the 1940s that produced 521 B-29 Superfortresses, including the Enola Gay and Bockscar used in the atomic bombing of Japan in World War II. The construction of Interstates 80, 480 and 680, along with the North Omaha Freeway, spurred development. There was also controversy, particularly in North Omaha, where new routes bisected several neighborhoods. Creighton University hosted the DePorres Club, an early civil rights group whose use of sit-in strategies for integration of public facilities predated the national movement. Following the development of the Glenn L. Martin Company bomber manufacturing plant in Bellevue at the beginning of World War II, the relocation of the Strategic Air Command to the Omaha suburb in 1948 provided a major economic boost to the area. From the 1950s through the 1960s, more than 40 insurance companies were headquartered in Omaha, including Woodmen of the World and Mutual of Omaha. By the late 1960s, the city rivaled, but never surpassed, the United States insurance centers of Hartford, Connecticut, New York City and Boston. After surpassing Chicago in meat processing by the late 1950s, Omaha suffered the loss of 10,000 jobs as both the railroad and meatpacking industries restructured. The city struggled for decades to shift its economy as workers suffered. Poverty became more entrenched among families who remained in North Omaha. In the 1960s, three major race riots along North 24th Street destroyed the Near North Side's economic base, with recovery slow for decades. In 1969, Woodmen Tower was completed and became Omaha's tallest building and first major skyscraper at , a sign of renewal. Since the 1970s, Omaha has continued expanding and growing, mostly to available land to the west. West Omaha has become home to the majority of the city's population. North and South Omaha's populations continue to be centers of new immigrants, with economic and racial diversity. In 1975 a major tornado, along with a major blizzard, caused more than $100 million in damages in 1975 dollars. Downtown Omaha has since been rejuvenated in numerous ways, starting with the development of Gene Leahy Mall and W. Dale Clark Library in the late 1970s. In the 1980s, Omaha's fruit warehouses were converted into a shopping area called the Old Market. The demolition of Jobber's