>I had no idea how fast blood moved but that's pretty incredible.

The speeds of various bodily processes are interesting. I have nerve damage. I was lying on the table at the doctor's office while they were testing the speed that signals travel from one part of my body to another. Being bored while the tests were going on, I did the math and calculated that the runners in the 100-meter dash at the Olympics run faster than my nerves send signals through my body. That seemed strange to me; I always thought of nerve signals being instant. It was several years ago so I don't remember the exact numbers.