A crowded footbridge during Osaka's rush hour dramatizes Japan's number one problem in 1970: population density. Since then, the problem has only worsened. Japanese government data show the country's population density increased from 720 people per square mile (281 per square kilometer) in 1970 to 870 per square mile (340 per square kilometer) in 2000.

(Text adapted from and photograph shot on assignment for, but not published in, "Kansai: Japan's Historic Heartland," March 1970, National Geographic magazine.)