Question: In what region of Africa is the country where the  Tartit (meaning "union"), band from the Tombouctou Region were formed located?
Sentence (from "Mauritania"): It is the eleventh largest country in Africa and is bordered by the Atlantic Ocean to the west, Western Sahara in the north, Algeria in the northeast, Mali in the east and southeast, and Senegal in the southwest.
Relevant evidence: No