They wore garments stimulated by using from CCosgames's blog

“In 1939, Myrtle R. Jones made sci-fi costumes for herself and her boyfriend Forrest J.  Cosplay Costume    Ackerman to put on on the very first WorldCon in New York City. 

They wore garments stimulated by using the 1936 sci-fi feature Things to Come, and regarded to be time-travelers to the event.   Genshin Impact Costume  

Since then, an increasing number of enthusiasts were dressing up and acting the element at geeky gatherings.