Osaka is Japan's third-largest city and a major commercial and industrial hub, with a population of over 19 million people in the greater Osaka area.
Hiroshima is a historic city on Japan's western coast, and is known for its Peace Memorial Park and Museum, dedicated to the victims of the atomic bombing.
The Great East Japan Earthquake of 2011 and subsequent tsunami devastated Japan's northeast coast and caused the Fukushima nuclear disaster.