The Most Torturous Method of Execution - Impalement

Now here is probably the most painful and interesting death method. Impalement as a method of execution involves a person being pierced with a long stake. The penetration could be through the sides, through the rectum, through the vagina, or through the mouth. This method leads to a painful death, sometimes taking days. The stake would often be planted in the ground, leaving the impaled person suspended to die. 

In some forms of impalement, the stake would be inserted so as to avoid immediate death, and would function as a plug to prevent blood loss. After preparation of the victim, perhaps including public torture and rape, the victim was stripped and an incision was made in the perineum between the genitals and rectum. A stout pole with a blunt end was inserted. A blunt end would push vital organs to the side, greatly slowing death. The pole would often come out of the body at the top of the sternum and be placed against the lower jaw so that the victim would not slide farther down the pole. Often, the victim was hoisted into the air after partial impalement. Gravity and the victims own struggles would cause him to slide down the pole. 

This method is extremely painful and was used by Neo-Assyrian Empire, Greek empire, and Roman Empire.