Throughout history certain leaders have acquired immense power at a human cost which is unimaginable. Although their governments promised progress, a revolution or a better future, millions of ordinary people had to pay the price in the form of war, executions, forced labour, famine and genocide.From medieval conquerors through to modern-day dictators, these five individuals have left behind some of the most horrific episodes in human history; although their names are still notorious, the extent of the suffering they inflicted is still hard to grasp.5. TimurTimur was a ruthless Turco-Mongol conqueror who is said to have killed about 17 million people during his campaigns of conquest; he established a large empire by means of violent military operations, causing devastation in all the areas through which his armies moved.He was famous for destroying whole cities and, as historical records state, left behind towers constructed from the skulls of his victims. It was because of his campaigns that he gained a reputation as one of history’s most dreaded conquerors.4. Pol PotIn 1975 the Khmer Rouge regime and its leader Pol Pot obtained control of Cambodia and as a result about 2 million Cambodians died in what was called the Cambodian Genocide.People were made to work and at the same time suffered from malnutrition, abuse, disease, and being executed. The government broke up whole communities as it tried to change Cambodia according to an extreme revolutionary ideology.3. Mao ZedongMao Zedong, a figure highly controversial, was in power in China during one of the most deadly phases in the nation’s history, and his policies were responsible for a massive famine and for widespread political violence.Some estimates claim that the Great Leap Forward resulted in about 55 million deaths as a result of famine, executions, and forced labour. Although the aim of the campaign had been to quickly turn China into a modern industrial power, it instead had disastrous consequences for millions of people.2. Adolf HitlerAdolf Hitler became leader of Germany in 1934 and later gained a bad reputation for carrying out the Holocaust. During the Nazi regime, persecution and mass murder were carried out on a huge scale.The Nazi regime of Hitler killed about six million Jews, which was roughly two thirds of the Jewish population in Europe. Millions of other people too were persecuted and murdered as Nazi Germany carried out its racist and expansionist beliefs.1. Joseph StalinJoseph Stalin brought about the transformation of the Soviet Union into an industrial superpower by means of imprisonment, executions, forced labour, and political repression. As Stalin got rid of those who were seen as enemies he imprisoned or executed millions in order to keep control through the use of fear.Almost 20 million people died as a result of famine, and the total number of deaths linked to Stalin’s rule is said to have been nearly 20 million. The suffering caused by his policies had a profound influence on the Soviet Union for many decades.Although these leaders belonged to various periods and were guided by different ideologies, their histories exhibit a disturbing pattern since their quest for power and control resulted in a devastating loss of life and left some of the darkest episodes in history.