The "boom" years of the 1920's were characterized by a growth in the use of Automobiles.
While looking at the history of the United States, the 'boom years' of the early 1920s were marked by a huge change in the way people traveled.
Personal transportation was shifting from horse-driven carriages to Automobiles, recently mass-produced by Ford.
At the time, the automobiles were a clear sign of growing economic might of the United States and the optimism of the early 1920s.
Some examples is the holocaust in 1933 and Armenia 1915
A. Slave Trade seems to be the only logical choice.
The man did not lead an empire like a Muslim leader should have.