Their excellent military tactics. Their warriors were well trained and as more and more tribes fell under their control, the larger the army became.
They are still alive today. Most modern Mexicans are descended from Aztecs. But their empire collapsed in the 16th Century, and Mexico was turned over to Spanish rule.
The Spanish Empire qualifies as such.
The Aztecs.
The Assyrians controlled their empire using a powerful military and by torturing dissidents.
The Aztec Empire.
The Aztec empire was destroyed some 450 years ago. The Aztects themselves are not dead, however; their descendants make up much of the population of present-day Mexico.
The Spanish Empire conquered Mexico in 1521.
The Aztec civilization.
March 13, 1325 - August 13, 1521.
The Songhai Empire.
Montezuma wanted a rich, powerful empire. He wanted lots of power over other Mexico cities.
The Spanish Empire held Mexico as an overseas territory for 300 years; from 1521 when they defeated the Aztec Empire until 1821 when the "insurgent" army entered Mexico City.