One key to the Incas’ expansion was their ability to produce and distribute a wide range of surplus crops, including maize, beans, potatoes, and meats. They constructed terraced irrigation systems for watering crops on mountainous terrain, perfected freeze-drying and other preservation techniques, built large store-houses, and constructed a vast network of roads and bridges. The Incas were still expanding when they too were overcome by Spanish invaders in the sixteenth century.
