Here in Sweden, massive investments in civil defense facilities were made after WWII and all over the country, a vast amount of installations have been built over the years. Where some have origins from the pre-WWII or WWII era, most are from between the late 1940s to the mid 1970s. These installations were upgraded over the years and in some cases completely redesigned to withstand chemical weapons and even nuclear explosions.
The method of choice was to build the bunkers deep down into the solid Swedish granite to give a good protection and camouflage. However, given the generally shallow level of ground water, meticulously designed pumping-, de-humidification- and heating installations were required to keep the indoor climate within reasonable bounds.
Although everything obviously was taken very seriously, I guess even the high-brass planners started to silently accept the futile in trying to protect civilians in a thermonuclear war being fought in a blazing speed with supersonic attack aircraft and missiles rather than with a slowly advancing infantry. As these installations were maintained by the local counties, I somewhat guess that this insight combined with the overall gloomy economic reality of the late 1970s triggered a long trajectory downwards for these installations. The final knock, as for so much else of the Swedish war organization, came with the end of the Cold War and most installations seems to have been abandoned in the mid-1990s. Where most installations have been stripped of everything and have been sealed carefully, others like this one seems to have been just left with all pumps and climate control being switched off for years.
It is an almost surreal experience to walk around in the complete darkness to see all these remains and try to recall what the scenario planning must have been just twenty years ago. Today the installation is far beyond just everything one could imagine, flooded and with water dripping everywhere. All stuff rusted or decomposed to debris, covered with slimy goo and thick furs of mould. Seeing all this, one can try to image what it was when it was all kept in perfect shape, ready for the upcoming Armageddon. Not a matter of if but rather a matter of when...