The Incas were way more advanced than the Aztecs. First off, The Inca covered way more territory with a larger population than the aztecs. The Aztecs couldn’t even expand out of Mexico, while The Inca expanded across Peru and Western South America. The Inca developed rich metallurgy opposed to The Neolithic Stone Age civilization the Aztecs were. The Inca had a better military. They used Gold, Silver, and Bronze in their Axes, Spears, Maces, and Halberds. Also The Inca were more physically fit than the pathetic small empire the Aztecs built. The Inca knew how to adapt to harsh mountains, in fact, The Second longest/highest mountain range in the world. The Inca also ran across mountains, making them more physically fit. They adapted to the Mountains, Rainforest, Deserts, Chaparrals, and Snow Mountains. That shows The Inca adapted more. The Inca had more physically fit soldiers with way better armor and weaponry consisting of metals than the aztecs. The Inca using their Weapons on the Aztecs would annihilate the way smaller Stone Age Aztecs. The Aztecs use stone and wood in their weapons. Oh and also The Inca stuffed alpaca wool in their armor, with robes, capes, crowns, helmets, and shields with capes as protection. The Aztecs would be annihilated. The Inca were way more advanced. They adapted to biomes, had way better metallurgy, built wondrous cities that still hasn’t fallen, such as Machu Picchu and Cusco, while Tenochtitlán was destroyed. The Inca also used Terraces, adapted to Mountains with Terraces as agriculture, domesticated corn, potatoes, and such, built long roads comparable to Rome, had better metallurgy, had larger territory and population, built actual unique cities instead of building non unique pyramids, and so on.