The Victorian Grade II-listed gem is believed to be the last remaining one of its kind still set in its original grounds in South Yorkshire.
A monster, dancing animals, an old wishing tree and a mysteriously missing headstone are just some subjects of the stories known about the Hackenthorpe landmark but there is still much more to be discovered.
That is why the Friends of Birley Spa, who are fighting to save the building, teamed up with Catherine Kennedy, PhD researcher at the University of Sheffield, to create a permanent record of its history.
Fiona Milne, of the Friends group, said: “One of the things that has been fascinating for us is everybody has got a story about Birley Spa.
“When we had our first mini open day in 2019 we were amazed at the people who came and the stories that came out.
"Then we bumped into people, had more events and we just so wished we had a means of saving all this information.
“We don’t need you to have exact times and dates but just give us a picture of what was there, what happened, what your experiences were and what your memories are.
“There is just so much out there and I know there are a lot of people who might need a gentle prod to say: your story matters.”
One early submission was from Sue Hall who said she and her sister would tiptoe across the grass to peer into the caged area on the lookout for a monster they believed lived beneath but were so scared they would run away before returning to do it again.
The archive will eventually become an open resource.
Ms Kennedy said: “Although loads of people in the community around Hackenthorpe have experience either themselves or in the family of the site and they know all sorts of things about it, it has never actually been formalised.
“Until knowledge is written down and recorded somewhere it tends to get ignored and brushed to one side so I thought it might be an interesting project and there has been quite a lot of enthusiasm in the history department at the University of Sheffield.
“Anyone who is remotely interested, who thinks they might have something, even if they think it’s not much or they are convinced nothing they have to say could possibly be of any interest, if they have the tiniest thing then it would be a really good idea for them to get in touch with the Friends of Birley Spa and talk to them about it.”
The project starts on February 15 but people can contact the Friends now via Facebook, Twitter or their website.
The Friends are continually working to bring the building back into public use, after it successfully campaigned to stop Sheffield Council selling it in 2018.
Talks between the council and community about its future are ongoing.
In these confusing and worrying times, local journalism is more vital than ever. Thanks to everyone who helps us ask the questions that matter by taking out a digital subscription or buying a paper. We stand together. Nancy Fielder, editor.