Some bright spark has come up with the idea of execution via suffocation using an enclosed room, removing oxygen and replacing it with nitrogen. The main reason for this is because the drugs for lethal injection are becoming harder to obtain.
We truly are sadistic people.
Only humans could possible come up with horrific ways to kill another human being and a lot have religious roots.
Crucifixion; being tied to a cross and left out in the elements to die a slow painful death.
Sawing; you are tied upside down between two trees and from the groin area you are sawn in half. Unfortunately you are alive for the most part of this act.
There is burning at the stake; pretty self explanatory. If there were mass burnings then most would die from monoxide poisoning rather than actually burning the victim,
Stoning: We are not talking drugs we are talking placed in a pit and have rocks thrown at you until you die.
I am sure you could come up with many more.
Oh my, the world we live in where killing another human is seen as justice.