Located on the South Hill of Spokane, is the Eastern Washington Historical Museum.
It is a branch campus of the Smithsonian Institute and features artifacts focusing on the eastern part of the state.
This web page focuses on items from Expo 74 that shows photos, uniforms, souveniers, and other items.
Expo 74 had some folklife themes to it. One of them was a section of this quilt signed by visitors.
Up close photos were taken in case you, or someone you knew, may have been attending the fair at the time.
Some of this collection shows that even an environmental themed world's fair, in the mid 1970s, didn't disregard advertising on ash trays and matchbooks.
The collection does show an outfit that Liberace wore when he was performing at the fair.