<span>the invention of elevators.</span>
They are Hong Kong, Singapore, South Korean and Taiwan. they got their names by earning very high growth rate ( they became rich very fast ) and fast industrialization between the early 1960s and 1990s.
To stop Communism from spreading to non-Communist countries
The sudden end to the slave economy would have had a profound and killing economic impact in the South where reliance on slave labor was the foundation of their economy