The region is physically diverse , featuring a number of highland areas , including the Sierra Madre de Chiapas and the Montañas Centrales ( Central Highlands ) , a southern littoral plain known as Soconusco and a central depression formed Coming_to_be by the drainage of the Grijalva River .

Soconusco had been incorporated Cause_to_amalgamate into the Aztec Empire , centred Placing in Valley of Mexico , and paid Commerce_pay the Aztecs tribute .