There have been cruel leaders at all times and ages, but the ruthlessness of these leaders surpass all in human history. One man’s hero is another man’s tyrant, a popular maxim goes. No matter how a historian tries to spin it, ordering a tower to be constructed out of live men stacked and cemented together with bricks and mortar is downright brutal. Here’s a list of the most ruthless leaders of all time: 1. Adolf Hitler This sickly psychopath and megalomaniac transformed the world in which we live, taking with him more than 11 million victims, in Europe and the…