The Great Wall Museum (Changcheng Bowuguan) is the country's most thorough museum dedicated to the history of the wall. Located inside the old town a few hundred metres south of the First Pass, it occupies a series of low Ming-style courtyard halls and runs visitors through the wall's history from the Warring States period (5th century BC) through the great Ming reconstruction and into the modern conservation era.
The exhibits include weapons, defensive equipment, construction tools, brick samples, garrison records, period maps and a detailed model showing the full 21,000 km of wall and how it was built and defended. The signage is in Chinese and English. Allow an hour or two; it is essential context for visiting Jiao Mountain and Old Dragon's Head.