Workers frame up new houses as a rural landscape is rapidly converted into a vast suburb while a construction boom continues in San Bernardino County during World Population Day on July 11, 2007 near Rancho Cucamonga, California. San Bernardino County and neighboring Riverside County in Southern California are among the fastest growing areas in the state and are expected to help drive the total state population to almost 60 million in 2050. In the 20th century, the world&#39;s population exploded from 220 million to 2.8 billion and that rate will increase exponentially. By 2008, 3.3 billion people, more than half the world&#39;s population, are expected to be living in urban areas.