city was devastated by the 1928 Okeechobee hurricane. The Depression years of the 1930s were a quiet time for the area, which saw slight population growth and property values lower than during the 1920s. The city only recovered with the onset of World War II, which saw the construction of Palm Beach Air Force Base, which brought thousands of military personnel to the city. The base was vital to the allied war effort, as it provided an excellent training facility and had unparalleled access to North Africa for a North American city. Also during World War II, German U-Boats sank dozens of merchant ships and oil tankers just off the coast of West Palm Beach. Nearby Palm Beach was under blackout conditions to minimize night visibility to German U-boats. The 1950s saw another boom in population, partly due to the return of many soldiers and airmen who had served in the vicinity during the war. Also, the advent of air conditioning encouraged growth, as year-round living in a tropical climate became more acceptable to northerners. West Palm Beach became one of the nation's fastest-growing metropolitan areas during the 1950s; the city's borders spread west of Military Trail and south to Lake Clarke Shores. However, many of the city's residents still lived within a narrow six-block wide strip from the south to north end. The neighborhoods were strictly segregated between White and African-American populations, a legacy that the city still struggles with today. The primary shopping district remained downtown, centered around Clematis Street. In the 1960s, Palm Beach County's first enclosed shopping mall, the Palm Beach Mall, and an indoor arena were completed. These projects led to a brief revival for the city, but in the 1970s and 1980s crime continued to be a serious issue and suburban sprawl continued to drain resources and business away from the old downtown area. By the early 1990s there were very high vacancy rates downtown, and serious levels of urban blight. Since the 1990s, developments such as CityPlace and the preservation and renovation of 1920s architecture in the nightlife hub of Clematis Street have seen a downtown resurgence in the entertainment and shopping district. The city has also placed emphasis on neighborhood development and revitalization, in historic districts such as Northwood, Flamingo Park, and El Cid. Some neighborhoods still struggle with blight and crime, as well as lowered property values caused by the Great