Staged to celebrate the completion of the Panama Canal, and drawing over 19 million visitors in only nine months, the Pan-Pacific International Expo rose like a literal jewel from the ashes of San Francisco's 1906 Earthquake and Fire.
A Century of Progress International Exposition was held in Chicago, Illinois from 1933 to 1934 to celebrate the city's centennial. The theme of the fair was technological innovation. Its motto was "Science Finds, Industry Applies, Man Conforms".
The 1939-40 New York World's Fair, located on the current site of Flushing Meadows-Corona Park, was one of the largest world's fairs of all time. The fair ran for two seasons and over 44 million people attended.
The Golden Gate International Exposition was held in San Francisco, California to celebrate the opening of the San Francisco-Oakland Bay Bridge and the Golden Gate Bridge. The exposition's first season ran from February 18, 1939 through October 29, 1939 and its second season was from May 25, 1940 through September 29, 1940.
The 1964/1965 New York World’s Fair, located on the current site of Flushing Meadows-Corona Park. The fair ran for two seasons and took place without sanctioning from the Bureau of International Expositions.
Expo 67 was held in Montreal, Quebec, Canada from April 27 to October 29, 1967. It was considered to be the most successful World's Fair of the 20th century, with over 50 million visitors and 62 nations participating.
Underground homes have not completely gone away. Here in hurricane alley there are several bldgs that both take advantage of the insulating aspect of soil as well as its resistance to wind and either burrow partway into the ground or pile dirt on top to protect from the tropical sun and heat. NOAA's new National Hurricane Center looks like a semi buried rocket launch bunker w mininmal windows peeking out to see if the coast is clear.
Anyone lucky enough to see southern California's Anza Borrego State Park Visitor Center steps in through the open north side with the rest of the building covered with sand and a collection of native desert plants adorning the roof
Beyond commercial applications, I occasionally but consistently read about the eccentric architect snuggling a custom home against a hunk of geology to varying degrees.
Then of course there are the hard cores who purchased and renovated defunct ICBM silos, and the wealthy James Bond villain wannabes who feel things may get so bad they build luxury underground lairs as a back up.