Suppose The Great Wall of China is the collective name of a series of fortification systems generally built across the historical northern borders of China to protect and consolidate territories of Chinese states and empires. Several walls were being built from as early as the 7th century BC, with the most famous being the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang.
Can we infer that "The Great Wall of China was built to protect against invasion"? Yes, no, or maybe?