Sub 2 hour marathon

Unlike things like the 4 minute mile, this used to be considered very possible, with the former world record holder seeming like they could hold the record. However, he died in a car crash shortly after his world record race. Then, recently, there were 2 sub 2 hour marathons that occured in the same race, with the 1:59:30 being the fastest. They ran at insane speed for a long period of time, with a pace of 5.9m/s or 21.2m/h. These are incredibly impressive speeds even for normal long runs, yet they ran it for an entire 42km. This goes to show how incredible these marathon runners are.