The Great Wall — Guardian of Civilization

It took two thousand years to build and cost more lives than any structure in human history. The Great Wall of China is not one wall but many — built, abandoned, rebuilt by successive dynasties across two millennia. At its peak it stretched 21,000 kilometers, staffed by a million soldiers who signaled danger with beacon fires that could carry a message across the entire length in a single day. It never fully worked as a military barrier. But as a statement about the seriousness with which China took the protection of its civilization, it is unmatched in human history.

These signs carry the watchtower, the beacon fire, the mountain passes, and the stone that remembers two thousand years of guardianship.