3 is the answer to the question
It was the world's longest humanmade structure at more than four thousand miles actually constructed from a series of smaller walls that were connected together built to guard against Mongol invaders.
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Answer: On the evening of Dec. 31, A.D. 192 to Jan. 1, A.D. 193 Narcissus, an athlete who trained Commodus in gladiator fighting, killed the emperor
Explanation:
