Who is the most influential leader of the last 500 years? Why?

Adolph Hitler

He changed the course of history more than anyone else

There are so many to choose from. One could argue the American Revolution really changed the world in fundamental ways, but it is wasn't really driven by an individual. I suppose Mao would be very high on the list because he introduced a new economic system, united a fracture country, defeated more than one powerful enemy, and shaped a nation that has over 1/3rd of the world population. I would also rank Gandhi very high for leading a peaceful revolution that liberated India and who was a moral leader. Others who would be high on the list are Lincoln (though the US was late in ending slavery), MLK, Thomas Jefferson, and Nelson Mandela.

Abraham Lincoln was President of the United States of America when it wasn't so united and should be considered the Father of Civil and Human Rights given America was the first people to fight a War to end Slavery. He definitely understood moral clarity.

George Washington, led the Revolution and tried a grand experiment in freedom.

Ben Franklin.