What caused the fall of the Inca Empire?

The fall of the Inca Empire was primarily caused by a combination of internal strife and external invasion. Civil war weakened the empire, particularly following the death of Emperor Huayna Capac, which led to a power struggle between his sons. This instability made the Incas vulnerable to Spanish conquistadors, led by Francisco Pizarro, who capitalized on the internal divisions and used superior military technology, including firearms and horses, to conquer the empire. Additionally, the introduction of diseases like smallpox by Europeans decimated the indigenous population, further contributing to the collapse.