If you are squeamish about pain and death, proceed with caution!
A Poor Boy
A kid wanted to climb into the chimney on top of the house. As he climbed in, he got stuck in the middle of the chimney with his back facing the ground.
So, he just waited there and slowly died. The skeleton was found after 8 years. (Xusiy)
Today I learned about a ninja who was killed by being buried up to his head and had dull bamboo shoots positioned around his neck and was slowly decapitated over the course of several days. (Meepweep)
Wallace was taken from the hall to the Tower of London, then stripped naked and dragged through the city at the heels of a horse to the Elms at Smithfield. He was hanged, drawn and quartered — strangled by hanging, but released while he was still alive, emasculated, eviscerated and his bowels burned before him, beheaded, then cut into four parts. His preserved head (dipped in tar) was placed on a pike atop London Bridge. It was later joined by the heads of the brothers, John and Simon Fraser. His limbs were displayed, separately, in Newcastle, Berwick, Stirling, and Perth. (MonkeysFanny)