Not my story but I was involved in a round about way. Back 1970ish.. out of the military and in college. I took a job as "the" maintenance man for a 20 story office building in the downtown area of my hometown. The building was built in the very early 1900's and had cast iron riser pipes (those being the pipes that pumped the supply water to the top floor where they then u-turned and went down to feed each floor water. The city changed it's water supply to "soft" water in the early 60's and so the pipes were lined with lime build up. In the two years I worked there, I walked into work a total of 6 times to find that one of the risers blew out when the lime inside had disappeared. I won't go into why management didn't replace them all after the first one blew. Oh.. it started life as a bank building so there was a vault in the basement next to my office in the basement.
Fast forward.. I go to my high school's 40th reunion. One of my former classmates is CIO of a company that now owns the building. After having a great evening, I visited him on Monday and got to see my old office... etc. The old maintenance office in the basement was the NOC. They were using the sub-basement for the datacenter. Nice digs and I told him the tales of the pipes breaking and flooding to midway up the basement wall. We had a few laughs and I returned back to the west coast.
More fast forward... you probably know where this is going. A few years later, I get a call.... "I remember you said you worked there. Facilities want's to know where the sump pumps are?". Me: "There used to be a steel door next to the vault and it's a stairway to the sub-sub basement where the sump pumps are located. Why?". The door had been covered during a remodel and everyone forgot about it, not that it would have helped. They had a riser break (one of the ones I had replaced many years ago) and flooded the sub-basement (DC) and the basement (NOC) and water was pouring out of the elevator shaft into the main lobby and then to street. I advised him to call the fire department and see if they could pump the water out after they hired a diver to go to the sub-basement and turn off the water supply.
All I know now is that the company is still there and their DC and NOC are on the 5th floor. Yes, my classmate is still CIO. I'm going to my 50th reunion in about 3 months and hope to see him.