"'39" was May's attempt to do "sci-fi skiffle". "'39" relates the tale of a group of space explorers who embark on what is, from their perspective, a year-long voyage. Upon their return, however, they realise that a hundred years have passed, because of the time dilation effect in Einstein's Theory of Special Relativity, and the loved ones they left behind are now all dead. Because the "year of '39" resembles 1939, some[5] have speculated that this is actually a song about the beginning of the Second World War but this is not the case. There are backing vocals by Mercury as well as very high and fairly low harmonies by Taylor, and some falsettos by Taylor.
Having named their albums A Night at the Opera and A Day at the Races after two of the Marx Brothers' most popular films, surviving brother Groucho Marx invited Queen to visit him at his Los Angeles home in March 1977 (five months before his passing). The band thanked him, and performed "'39" a cappella.[6]
George Michael performed "'39" at the Freddie Mercury Tribute Concert in April 1992.[7][8] Michael cited this song as his favourite Queen song, claiming he used to busk it on the London Underground.[9]
Counting all of the original songs in album order, starting with Keep Yourself Alive (on the first Queen album) all the way through to "'39", this song falls 39th in chronological order.