Scientists at the European nuclear research centre CERN have uncovered an archive of images from its first 50 years - and are asking for help in deciphering what is going on in them.
Archivists are digitising more than 250,000 hard-copy images, dating from 1955 to 2005.
They are being processed in batches, with the first focusing on around 120,000 taken between 1955 and 1985.
CERN said that some descriptions exist but are incomplete.
The archivists are looking, in particular, to identify the people in many of the images.
They said they were also looking for help with descriptions of equipment, "and we believe that much of this information could be crowd-sourced from the CERN community."
Dr Sue Black, who was a key figure in the campaign to save Bletchley Park, where the German Enigma code was broken during World War Two, praised the project.
"It's so important to archive and share our scientific history. It helps us all to understand the work that has been carried out in the past, which helps us to better understand and appreciate the research that is being carried out today - and to be able to correctly put current research into context," she told the BBC.
"Crowdsourcing the information related to these images is a fabulous approach to public engagement and one which other institutions - scientific or not - would be wise to follow.
"It engages public interest and imagination in a way that is interesting and exciting. It will also be a great exercise in demonstrating the power of crowdsourcing, possibly to an audience that has not experienced it before," she said.
John Graham-Cumming, author of The Geek Atlas: 128 Places Where Science and Technology Come Alive, said: "What I love about these photographs is that many look like they are stills from a 1960s science fiction film about the future, when in fact they are the real thing".
CERN said it would release more batches of mystery photographs and is asking for help from any member of the public who might be able to offer information.