Nostalgic pictures show a frozen-in time-bar from the 80s, complete with dusty bottles of Martini and Corona lemonade.
The incredible slice of night life from days gone by was discovered by workers above an old BHS store on Princess Way in Swansea city centre.
The bar, which has not seen any patrons since the 1980s, has been left untouched since it closed its doors decades ago.
Inside what was once the Cavalier bar dusty drinks bottles sit alongside an old bar menu offering pub grub for £1.50 and horse fixtures from over thirty years ago.
This monument to nights-out past will soon be torn down, as Swansea Council begins work to turn the huge empty BHS building into a library and community hub, WalesOnline reports.
Entry to the bar used to be found up a stairwell behind a large wooden door facing onto Princess Way. Once upon a time anyone entering would likely have been greeted by the sound of chatter and clinking glasses - possibly talk about the odds for the 2.30pm at Worcester.
Now, in the gloomy space, a Corona glass lemonade bottle still stands on the bar, alongside a bottle of sweet vermouth Martini Rosso and a scrawled menu advertising bar meals of lasagne, cottage pie and faggots and peas, costing just £1.50 each - that wouldn't even buy you a drink in most bars these days.
There's also an elaborate, hand-painted entrance sign, a mosaic wall and a poster from 1988 which announces the horseracing fixtures at Bangor, Hereford, Ludlow and Worcester.
Council cabinet member Elliott King said: “We have a great future planned for this large building right at the heart of the city centre. It’s also interesting that our work there has revealed some unexpected social history from the building’s past - the old Cavalier - in a small part of the structure.
“Cabinet colleagues have some recollections of who owned and managed the bar – but I’d be really interested for the people of Swansea to let us have their memories using #SwanseaCavalier on social media.”
The former Cavalier bar and the rest of building have been secured for safety reasons and the hub is due to open in 2024 once it has undergone construction.