S1, E4: Under the leadership of Emperor Moctezuma, the great Aztec civilization reached its zenith. The jewel in its crown was the beautiful city of Tenochtitlan, a melting pot of extraordinary arts and culture. But Moctezuma’s empire was fragile. His fierce grip on power created many enemies. The arrival of the Spanish in 1519, under Hernan Cortes, would prove the most disastrous moment in Aztec history.