Title: Greece.
Question: Rebetiko was the base of what? 

Title: United States Air Force.
Question: What fields of study in the COT are included in this area of the USAF? 

Title: British Empire.
Question: Britain's dominant position in world trade over some countries' economies has been called what?

Title: Charleston, South Carolina.
Question:
How many free people of color lived in Charleston in 1860?