Kuyalnik used to be a very famous mudbath. 200 years ago doctors concluded that local mud had magical properties and convinced the city authorities to build a mudbath here. People from all the Empire used to come here for improving their health. Soviet people liked mud treatment as well. They even had to build three more buildings to accept all comers.
Local mud could allegedly heal any desease - starting from skin deseases and ending with osteochondrosis and prostatitis. It's easy to treat with mud: one just needs to apply it over the body and wait till everything becomes well... Or one can take a mudbath.
They used to bring mud to the place by boats. Later they started to use automatics. This pipe was used to pump the mud from the firth to the sanatorium.
This is how it looks from the side of the firth.