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The World's Fair (also called the International Exposition or Expo) is an international festival of arts and sciences held every five years. Participating countries present artistic and educational displays in national pavilions to showcase their country's history or world issues.
The first international exhibition in the form we know it today was held in London in 1851. Paris hosted several world's fairs in the late 19th century, and the idea was soon copied by several other cities.
Rising popularity of the World's Fair concept brought conflicts of schedule and interest. In 1928, a convention to schedule regular World's Fairs was created, and the International Exhibition Bureau was created to coordinate World's Fair organization.
List of World's Fair sites