It’s no coincidence that the speeches that changed the world were delivered by some of the greatest leaders of all time.

These are the people who courageously sought to advance society, to right the wrongs of government, to push forward in areas where no one ever thought change was possible — and whose words inspired those around them and, for all who read their speeches today, encourage them still.

Scroll through the gallery to see who changed the world and how — and what they said that made the difference.