Revenge is an age-old phenomena - it has been around since human beings first came into existence, and has often been exacted in brutal form. Allegedly revenge is sweet. Supposedly retribution should be swift. But should all negative actions provoke a reprisal?
Most human beings, having suffered injury or wrong at the hands of others, have an urge to exact retribution on those who have caused them pain - although often they decide not to act upon such instincts.
Indeed, for Christians the Bible holds a clear position on revenge, with Romans 12:19 stating: "Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, 'VENGEANCE IS MINE, I WILL REPAY', says the Lord."
But not all Christians - or those of any faith - leave vengeance and retribution to God. In fact, one example of brutal revenge from history occurred during the Fourth Crusade - when a blind man led Christian soldiers to completely destroy Constantinople in revenge for losing his eyesight. Other examples include an American politician who killed his rival in a duel because he lost an election, Jewish groups exacting revenge on Nazis for the Holocaust, and Israeli secret agents hunting down Palestinian dissidents in response to the Munich Olympics Massacre.
So here are 10 of the most brutal acts of revenge in history - and some of them make for disturbing reading...