1. The Andes Mountains: The Andes Mountains formed a formidable natural barrier along the eastern border of the Inca Empire. The rugged terrain, high altitudes, and treacherous passes made it difficult for invaders to penetrate the empire from this direction. The Incas constructed many fortifications and defensive structures to further strengthen their defenses along the mountain range.
2. The Atacama Desert: The Atacama Desert, located in the northern part of the Inca Empire, acted as a natural barrier in the west. The desert's extreme dryness, lack of vegetation, and harsh conditions discouraged large-scale invasions and made it difficult for armies to sustain themselves during prolonged campaigns.
3. The Amazon Rainforest: The Amazon Rainforest, located in the eastern region of the Inca Empire, presented a formidable natural obstacle. The dense jungle, thick vegetation, and abundance of rivers and waterways made it challenging for invaders to navigate and establish supply lines effectively. The Incas had a deep understanding of the rainforest and utilized it as a defensive advantage by building hidden settlements and strategic fortifications.