Human body
The brain cannot feel pain
Brain tissue has no pain receptors. That is why surgeons can operate on an awake patient, asking them to talk or play guitar to make sure nothing vital is cut.
Brain tissue has no pain receptors. That is why surgeons can operate on an awake patient, asking them to talk or play guitar to make sure nothing vital is cut.

It is about 2% of your body weight but consumes roughly 20% of your calories and oxygen — running on around 20 watts, less than a dim light bulb.

Each one can connect to thousands of others, making roughly 100 trillion synapses — a wiring diagram no machine has yet come close to matching.