There's many abandoned government bunkers in Easter Europe. Check out YT vids of URBEX (Urban Explorers). They basically explore abandoned buildings. Like bunkers, warehouses, Fukushima city, mansons.
Their #1 rule is do not break or steal anything. So they cannot bust a door to gain entree.
The Fukushima urbex is eerie. Get shelves full of Xbox's in the department store, canned./bottled food still on the shelves at the supermarket all nicely arranged, cars at a dealership, etc...
Had 1 in Canada where they went into a mansion. They found bank statements that had millions on them and all only a year old, un-deposited checks for 6 figures. Makes you wonder what kind of person has that much money where they don't deposit a check and haven't been to their mansion in a while. Even found gold and diamonds in a safe that had the combo on a post it stuck to the safes door. And rule #1, they put everything back into the safe and stole nothing.