One of my best memories of all time was going to the 1964-65 New York World's Fair. However, it didn't get official recognition since, among other reasons, it ran for two years instead of the one six-month period stipulated by the Bureau International des Expositions, which decided to recognize the 1962 fair in Seattle. Still a fantastic experience for a 10-year- old kid.
also, glad to see this type of international gather is a bit more varied by continent than another i could mention
neither has africa yet tho
guessed Milan, Rome, Venice, and Palermo for Italy and Austin, Dallas, Houston for Texas and ended up missing the one city for both