What was huayna capacs greatest contribution to the inca empire

Huayna Capac built two important Inca roads from Tumbez to Pachacamac and the other from Pachacamac to Cusco.

Explanation:

Huyana Capac was a prodigious combatant of Inca Empire and he extended his empire. He built his capital city in Quito.

He made some developments by building two important roads and many small houses were built for the messengers of Inca Empire and it was called Coptras. He died out of small pox. His body was brought to Cusco and his heart was in Quito.

Before his death, he made grave mistake of allocating the empire between his brothers and this brought up many civil wars and thus Inca Empire faced the downfall.