Based on the clue 'at over 4 miles in length a wall built in the 400s...', what is the answer?

Based on the clue 'at over 30 years this west virginian is currently ...', what is the answer? Based on the clue 'at over 330 pounds you might say this wilson prede...', what is the answer? What is associated with: at over 3500000 square miles this desert covers an area larger than australia? What is associated with: at over 36000 feet its the deepest spot in the north pacific or anywhere else on earth? Based on the clue 'at over 60 million square miles this ocean covers ...', what is the answer? Based on the clue 'at over 80 hutu 1 of 2 countries', what is the answer? Based on the clue 'at oxford to be sent in this direction is to be ex...', what is the answer? Based on the clue 'at panquetzaliztli an aztec festival those not per...', what is the answer?