We used to climb up on the town water tower
We would drive as fast as possible and go over "thrill hill" - basically a one lane road with a steep hill that was peaked on top so when you went fast over it in a car, you "lost" your stomach. If we had ever met anyone coming up the other side - well that would have been the end of us all.
I rode bikes everyday and motorcycles too - no helmet
Of course, no seatbelts
I swam in the farm pond and the stock tank
I ran around the farm with all the animals, farm equipment, etc. completely unsupervised
I left the house in the morning and came home in the evening.