I'd say the combustion engine, even though it was toyed with in the mid-west during the cowboy era, it wasn't until after the Civil War in which it was a fully effective gasoline powered engine.
Answer:
Massive profit opportunities, increased access to raw goods, more political power and colonization outside Europe, and the rise of the Industrial Revolution.
To be classed as a citizen in fifth-century Athens you had to be male, born from two Athenian parents and over eighteen years old, and complete your military service. Women, slaves, metics and children were not allowed to become citizens.
"The Third Crusade" is your most reasonable answer.
The size of the country. the soviet union had immediate access to resources, the germans couldn’t stretch their resources as far as they had come. add on the cold, the germans had quite the hard time