On April 4, 1925, the US Post Office issued the first three stamps in a multi-year series honoring important events and people from the American Revolution. The stamps were issued for the sesquicentennial (150th) anniversary of the Revolution.
The 1933 World’s Fair opened in Chicago, Illinois, on May 27, 1933. The fair was so popular, it ran for two years and was the first international fair to pay for itself.
On April 17, 1958, the Brussels World’s Fair, also known as Expo ’58, opened its doors. It was the first major official world’s fair after WWII.
On February 20, 1915, the Panama-Pacific Exposition opened in San Francisco, California. The expo was a celebration of the city and the Panama Canal.
On May 31, 1926, the Sesquicentennial International Exposition opened in Philadelphia, Pennsylvania. It was planned to mark the 150th anniversary of the signing of the Declaration of Independence and the 50th anniversary of the 1876 Centennial Exposition.
On February 18, 1939, the Golden Gate International Exposition opened in San Francisco, California. Initially planned to honor the completion of the Bay Bridge and the Golden Gate Bridge, it was expanded to honor all the countries and continents surrounding the Pacific.