Jiayuguan is the western terminus of the Ming Great Wall, considered the “First and Greatest Pass Under Heaven.” Built in 1372, this massive fortress guarded the narrowest point of the Hexi Corridor — the only route between the Mongolian and Tibetan plateaus.
The fort is legendary for a single brick: the “Ratifying Brick” placed by the master craftsman Yi Kaizhan, who calculated the exact number of bricks needed for the gate tower. When officials found one extra brick, he declared it was placed by the gods to stabilize the wall — and it remains there to this day.