The 1967 International and Universal Exposition or Expo 67, as it was commonly known, was a general exhibition, Category One World's Fair held in Montreal, Quebec, Canada, from April 27 to October 29, 1967. It is considered to be the most successful World's Fair of the 20th century with the most attendees to that date and 62 nations participating. It also set the single-day attendance record for a world's fair, with 569,500 visitors on its third day.