During the Cold War, this bunker was built as an auxiliary hospital.
The overlying school was opened in the 60s while the hospital was officially inaugurated in the 80s.
It offered 2,370 places and never went into operation.
At the turn of the millennium, it was relieved of its responsibilities, the inventory transferred to other states, and the hospital will be soon demolished.
The rehab center consists of several buildings in very different state of preservation. While some rooms of the spa hotel still look almost as good as new, an outbuilding (possibly former apartments of employees) is already partially collapsing.
Unfortunately I don't know anything about the history.