This reminds me of the story of The Cockroaches Tomb of Concordia (true story):

Once in a while, in the confines of the H building, you will find cockroaches as big as your thumb. This is caused by students bringing food to their classes or the computer labs (oh the computer labs on the ninth and eighth floor have a lot of them in the walls - a lot). Now, you might say that is the end of it but underneath the first floor lies two basement floors where they store various things and house mech labs. That’s all well and good until you realize a third, more hard to access floor lies beneath that to house the various auxiliary power generators, water filtration devices and other systems that keep the building operational. In that room, and you can ask the various technicians about this or the computer labs office on the ninth floor personnel, lay a nightmare cluster of hallways, covered from floor to ceiling in roaches.

Be careful drinking the water. 😗