Ask people on the street who the most influential people of the 20th century were, you’ll probably get a lot of answers; Hitler, Stalin, Marx, Lenin, etc. I have a different answer:
Hiram Maxim With His Machine Gun
Maxim’s invention of the belt-fed water cooled machine gun would spell the end of Europe’s geopolitical significance by the end of the 20th century. From 1914 to 1918 the great empires of Europe made suicidal charges into the wall of lead laid down by Maxim’s invention, and lost entire generations of young men in the process. World War I greatly weakened Britain, and laid the foundation for the rise of the Third Reich in Germany. World War II finally killed off the British Empire, along with every other colonial European power. The face of the world would never be the same again.
Interesting fact, his son created the first suppresors/silencers for guns and mufflers for cars.