Haibao knowhow

Q: Which countries have hosted World Expos?

A: The major countries include Britain, France, the United States, Germany, Belgium, Canada, Japan, Australia, Spain, Italy, Portugal and South Korea. The US has hosted the most expos (14), while Paris as a city has hosted the most expo-related events (7). Five-time host Japan was the first Asian country to welcome the World's Fair, with Osaka shouldering the responsibility in 1970.

Q: When did the expo first begin focusing on one theme?