One path to understanding history, collecting memorabilia and learning a great deal about world culture is through the study of world's fairs and international expositions. If you study or collect fairs, the following list should be a handy reference. The list includes all major sanctioned expositions and world's fairs from 1851 to 1992, as well as most of the second-tier expositions. The events are listed chronologically from London's expo at the Crystal Palace in 1851, generally accepted as the first world's fair, through the 500th anniversary of Columbus' voyage.

Like everything from Olympic Games to tobacco spitting championships, world's fairs are sanctioned by an international organization. And one criterion, odd as it may seem to the intelligent mind, is that to be "official" a world's fair must be held at least five years after the previously sanctioned fair. Thus, as aficionados of fairs know, the 1962 Seattle World's Fair Century 21 Exposition was indeed sanctioned and quite genuine as international expositions go. But New York, home to the mammoth 1964–65 world's fair, was not a sanctioned event, no matter how large, famous or wonderful, because it was held a mere two years after Seattle's.

We have included all major sanctioned fairs, as well as the larger non-sanctioned events, plus many significant smaller international fairs. We've also included brief notes and/or titles of the fairs that were unusual or not commonly known. For any committees, countries or collectors we have offended by omitting your favorite fair, we do apologize. If one simply glances at the list of "world's fairs" on Wikipedia, the qualifications for inclusion are merely staging a fair, regardless of scope or criteria. Between an 1850 fair in Tunis and the end of the 19th century, Wikipedia lists an amazing 114 fairs; it shows another 118 through 1939. Interestingly, the pace slowed dramatically with "only" 31 fairs noted between 1940 and 1999.

The U.S. Government Building at the 1905 Lewis & Clark Exposition in Portland