Like millions of others who attended Osaka's 1970 World Exposition, Kazuhiko Masuda, who was just 10 years old at the time, can still vividly recall it today.

"I remember standing in line for a very long time to see a moon rock brought back by the Apollo astronauts," the now 56-year-old Osaka-based architect said. "The Expo was all about the future, and everyone felt excited at what it might bring."

But although the city of Osaka hopes to rekindle the magic of 1970 by hosting another World Expo in 2025, lightning — as the saying goes — never strikes the same place twice.