TIL that the world's quietest room is located at Microsoft's headquarters and registers -20.35 dBA, making it quieter than a human heartbeat

https://www.guinnessworldrecords.com/world-records/quietest-place

https://www.reddit.com/r/todayilearned/comments/15600fa/til_that_the_worlds_quietest_room_is_located_at/