A family friend of ours was into collecting anvils, for whatever reason. I remember one visit we all went to a vineyard where they had a demonstration of anvil firing.

They placed gunpowder between two playing cards between two anvils. It was pretty amazing, the shock wave would sting your shins, the top anvil would go straight up and come straight down hitting the bottom anvil with a satisfying clang, and all the kids would look around and for the burnt halves of playing cards.