I would say that a good candidate is the idea of democracy: from Greece and Rome.
The best option from the list would be "World War I" since the Great migration saw the mass-movement of blacks from the South to the North, and this was mainly due to an increase in jobs due to WWI.
Answer: Old Glory.
Explanation: Old Glory is a nickname for the flag of the United States. The original "Old Glory" was a flag owned by the 19th-century American sea captain William Driver (March 17, 1803 – March 3, 1886), who flew the flag during his career at sea and later brought it to Nashville, Tennessee, where he settled.
