This time we will go down to the mysterious underground of Serpukhov, the Moscow region.
The bomb shelter is rather odd: starting from its exposure to a blast wave (all rules of protective shelters embedding are violated) and finishing with its poor condition (it's abandoned and flooded) and bad planning.
For some unknown reason it was built from two not interconnected parts. Each block has its own entry and its emergency exit. There are a DPS and a filtration unit in one block and another filtration unit in the second one.