Great Wall of China: Who Built It, When and How Long?
The Great Wall of China: who built it, when and why, how long it is according to China's official survey, and whether you can really see it from space.
It snakes across mountains, deserts and plateaus in northern China like an endless stone dragon. The Great Wall of China is the longest defensive structure ever built and one of the New Seven Wonders of the World. But who built it, when, and why? How long is it really? And can you actually see it from space?
What is the Great Wall of China?
The Great Wall of China is not one continuous wall. It is a network of walls and fortifications built by successive Chinese states and dynasties over more than 2,000 years. Along with the walls themselves, it includes watchtowers, forts, fortified mountain passes and trenches.
It runs across northern China, from near the coast in the east to the deserts of Gansu province in the west. UNESCO added it to the World Heritage List in 1987, and in 2007 it was voted one of the New Seven Wonders of the World.
Who built the Great Wall of China?
No single person or generation built the wall. Even so, one name is tied to it more than any other: Qin Shi Huang, who became the first emperor of a unified China in 221 BC.
Before unification, China’s rival kingdoms each built their own border walls. After it, around 220 BC, Qin Shi Huang ordered several of these northern walls to be joined into a single defensive system. Chinese historical records say the general Meng Tian oversaw much of this work.
The people who actually hauled the earth and stone were mostly soldiers, conscripted peasants and convicts. The work was brutal, in steep mountains and harsh winters, and many died building it, though there are no reliable figures for how many.
When was the Great Wall of China built?
The earliest walls date to around the 7th century BC, and building and repair continued on and off until the 17th century AD.
| Phase | Approximate date | What happened |
|---|---|---|
| Rival kingdoms | From about the 7th century BC | Separate walls built to guard borders |
| Qin dynasty | About 221–206 BC | Northern walls linked into one system |
| Han dynasty | 206 BC – AD 220 | Wall extended west to protect trade routes |
| Ming dynasty | 1368–1644 | Large-scale rebuilding in stone and brick |
| World Heritage listing | 1987 | Recognised by UNESCO |
Most of the wall tourists walk on today near Beijing, at sections such as Badaling and Mutianyu, dates from the Ming dynasty. The Ming built solid brick-and-stone sections, replacing the rammed earth that was common in earlier walls.
Why was the Great Wall of China built?
Its main purpose was to protect the farmland of northern China from raids by nomadic peoples from the northern steppe. But it was more than a barrier:
- Watching and warning: watchtowers passed signals along the line using smoke by day and fire by night.
- Controlling movement and trade: gates regulated people and caravans, especially along the Silk Road.
- Moving troops and supplies: the walkway on top served as a road through rugged mountains.
Did you know? Chinese researchers have found that Ming builders mixed sticky rice soup into their lime mortar, making it stronger and more water-resistant. It is one reason some sections have survived for centuries.
How long is the Great Wall of China?
It depends on what you count as “the wall”. In 2009, China announced that the Ming-dynasty wall alone measures about 8,851.8 km, from Hushan in Liaoning province in the east to the Jiayuguan Pass in Gansu in the west. That figure includes walls, trenches and stretches of natural barriers such as hills and rivers.
Then in 2012, after a field survey begun in 2007, China’s State Administration of Cultural Heritage announced that the full length of the Great Wall of China, counting every dynasty’s walls, is about 21,196 km.
| Measurement | Approximate length |
|---|---|
| Ming-dynasty wall (2009 survey) | About 8,850 km |
| Whole wall, all dynasties (2012 survey) | About 21,196 km |
| Whole wall in miles | About 13,170 miles |
Its height and width vary a lot. On restored stone sections near Beijing the wall is usually a few metres tall and can reach about 7–8 metres, with a walkway wide enough for several people to walk side by side. Many older earthen sections in the west are badly eroded and much lower.
Can you see the Great Wall of China from space?
This is one of the world’s most famous myths. In reality, the Great Wall of China is not visible to the naked eye from space under normal conditions, despite its enormous length. It is very narrow compared with its length, and its colour blends into the surrounding soil and rock.
China’s first astronaut, Yang Liwei, said after his 2003 flight that he did not see it. NASA has also said the wall is generally not visible to the unaided eye from low Earth orbit. Some astronauts have photographed it with zoom lenses, and a few say they glimpsed parts of it in ideal lighting when they knew exactly where to look. Seeing it from the Moon is completely impossible.
If you love ancient wonders, read how the pyramids were built and who built Petra.
Frequently asked questions
Which emperor built the Great Wall of China?
The wall is usually credited to Qin Shi Huang, the first emperor of unified China, who linked the northern walls around 220 BC. But building began centuries before him and continued long after, and the best-preserved sections today were built by the Ming dynasty.
How long is the Great Wall of China in km?
According to China’s official survey announced in 2012, the wall in all its sections across every dynasty is about 21,196 km long. The Ming-dynasty wall alone is about 8,850 km.
How long did it take to build the Great Wall of China?
It was not built in one go. Construction came in phases over more than 2,000 years, from around the 7th century BC until the end of the Ming dynasty in 1644.
Is the Great Wall of China visible from space with the naked eye?
Not under normal conditions. The wall is narrow and similar in colour to its surroundings, and Chinese astronaut Yang Liwei confirmed he could not see it. It cannot be seen from the Moon at all.
Where is the Great Wall of China located?
In northern China, crossing many provinces from east to west. The most popular sections to visit are near Beijing, such as Badaling and Mutianyu.
Key takeaway
The Great Wall of China is not a single wall but a network of fortifications built over more than 2,000 years. Emperor Qin Shi Huang linked its northern walls around 220 BC, and the Ming dynasty rebuilt its most famous sections in brick and stone. Its total length is about 21,196 km according to the 2012 survey, but contrary to popular belief, you cannot see it from space with the naked eye.
