# Great Wall of China
Confidence: high
Last verified: 2026-05-22
Generation: ai_assisted


## TL;DR

The Great Wall of China is a series of fortifications built across northern China from the 7th century BCE through the Ming Dynasty (1368-1644). Total length: 21,196 km (with all branches). Purpose: defense against nomadic invasions from the north. Contrary to myth, it is NOT visible from the Moon with the naked eye.

## Core Explanation

Ming Dynasty sections (near Beijing) are the most visited (Badaling, Mutianyu). Original walls: rammed earth; Ming: brick and stone. Watchtowers every few hundred meters for signaling (smoke by day, fire by night). Labor: soldiers, peasants, prisoners — hundreds of thousands died during construction. Not a single continuous wall — multiple walls built by different dynasties.

## Further Reading

- [The Great Wall (John Man)](https://www.hachettebookgroup.com/titles/john-man/the-great-wall/9780306817670/)