Tradition gets stamp of approval in Shanghai

Expo 1967 in Montreal launched an Expo souvenir phenomenon that continues to this day. No doubt, 43 years later, there are millions of them scattered around the world, in closets, in attics and in basements - the treasured Expo passport. The passport became so identified with Expo that it has appeared in promotional materials.

The souvenir has changed little in that time. Originally tied to a one-day, three-day, seven-day or season-pass ticket, the passports are now sold independent of entry tickets. That's probably a good thing since some recent Expos have had so many countries participate that you might need two or three of the tiny books to fit all of the rubber stamp images.

Sometimes the rubber stamps are at the entrance of a pavilion or sometimes at the exit. At some Expos, mostly children collect the images; at others, everyone joins in. At Zaragoza, Spain's Expo 2008, Croatia's stamp went missing, forcing pavilion staff to hand draw the design - definitely a unique souvenir.