The Great Wall of China is a series of fortifications built by ancient Chinese states and is the world’s longest border wall. It stretches along China’s historic northern borders. Its Chinese name is the “Ten Thousand Li Long Wall” (萬里長城 / 万里长城, Wànlǐ Chángchéng). The word “li” is a Chinese unit of length. However, the wall is longer than 10,000 li. The number 10,000, or wàn (萬 / 万), also signifies infinity or an immeasurable quantity in Chinese. Therefore, the phrase can be interpreted as “a wall of unimaginable length”. However, when referring to the Great Wall, the Chinese dynasties following the Qin generally used various terms such as “borders” (塞, Sài), “walls” (垣, Yuán), “barriers” (障, Zhàng), “outer forts” (外堡, Wàibǎo) and “border walls” (边墙, Biānqiáng). The sections of the Great Wall in the southern Gobi Desert and the Mongolian steppes are sometimes referred to as the “Genghis Khan Wall”, even though Genghis Khan himself did not construct any wall or permanent defensive line.
The Chinese, who began employing wall-building techniques during the “Spring and Autumn Period” between the 8th and 5th centuries BC, constructed even more extensive fortifications throughout this period and the subsequent “Warring States Period” to defend their borders; all the states of Qin, Wei, Zhao, Qi, Han, Yan and Zhongshan did so. However, the Qin, Zhao and Yan states also used their border walls to repel certain attacks and protect the country’s northern borders. King Ying Zheng of Qin defeated his final rivals in the 200s BC and unified China as the first Emperor of the Qin Dynasty. King Zheng, who proclaimed himself Emperor “Qin Shi Huang”, ordered the demolition of certain sections of the boundary walls that remained from the former states and ensured that new walls were built to connect the fortifications stretching along the northern border. Many successive dynasties constructed and maintained numerous boundary walls. Today, very little remains of the Qin Wall. The best-known sections of the Great Wall of China are those built by the Ming Dynasty (1368–1644).
These border walls, built by various dynasties, consist of multiple courses. Collectively, they stretch from Liaodong in the east to Lop Lake in the west, and from the modern-day China-Russia border in the north to the Tao River (Taohe) in the south. Recent research has concluded that the Great Wall of China was actually longer in the past than it appears today. In 2009, a previously unknown 180-kilometre section of the Ming Wall, concealed by hills, ditches and rivers, was discovered with the aid of infrared rangefinders and GPS devices. In March and April 2015, nine further sections, believed to be part of the Great Wall and totalling over 10 km (6 miles) in length, were discovered along the border between the Ningxia Autonomous Region and Gansu Province. With these latest discoveries, the total length of the Great Wall of China is 21,196.18 km (13,170.70 miles), roughly following an arc that marks the boundary of the Mongolian steppe.
Until the Ming Dynasty, the Great Wall was primarily constructed from rammed earth, stone and timber. However, during the Ming Dynasty, materials such as bricks, tiles, lime and stone were used extensively in many sections of the wall. The size and weight of the bricks made working with them easier than with earth and stone, thereby speeding up construction. Furthermore, bricks could bear more weight and were more durable than compacted earth. Stone could also support its own weight better than brick; however, it was more difficult to work with. For this reason, rectangular-cut stones were used only at the base of the walls, along the inner and outer edges, and at the entrance gates. The ramparts, meanwhile, covered the uppermost part of the vast majority of the walls.
Across the Great Wall of China, the walls are generally 4–6 metres high, with a base width of 7 metres and a top width of around 6 metres. Horses and carts can travel along the thicker sections. Along the thick boundary walls, there are parapets, arrow slits, watchtowers and beacon towers. Palaces, military barracks, garrison stations and temples can also be found in places along the wall. In some areas, the walls were constructed in several tiers to allow for a stepped defence system. Today, the Great Wall’s defence system is generally regarded as one of history’s most impressive architectural achievements. The purposes of the Great Wall included not only defence but also border controls, communication via smoke or fire signals, the imposition of taxes on goods transported along the Silk Road, the regulation or promotion of trade, the control of migration, and serving as a bridge to facilitate transport corridors.
One of the most striking sections of the Ming Great Wall, which is among the best-known parts of the Great Wall of China, is where the border wall climbs up extremely steep slopes at Jinshanling. The wall is 11 km (7 miles) long at this point. Its height varies between 5 and 8 m (16 ft 5 in to 26 ft 3 in). The base is 6 m (19 ft 8 in) wide, narrowing to 5 m (16 ft 5 in) at the top. The Shanhai Pass, situated on the edge of the Bohai Gulf, is considered the traditional terminus of the Great Wall and is known as the ‘First Pass Under Heaven’. The section of the wall at Shanhai Pass where it meets the sea is known as the “Old Dragon’s Head”. Located 3 km (2 miles) north of Shanhai Pass is the Jiaoshan Great Wall (t焦山長城, s焦山长城, Jiāoshān Chángchéng), the site of the Great Wall’s first mountain; 15 km (9 miles) north-east of Shanhaiguan lies Jiumenkou (t九門口, s九门口, Jiǔménkǒu), the only section of the wall constructed as a bridge.
The entire Great Wall of China is a sight of breathtaking beauty. However, the sections surrounding Beijing are particularly famous. These sections are frequently restored and are regularly visited by tourists today. The Badaling section of the Great Wall near Zhangjiakou is the most famous part of the wall. This is because, in addition to being the first section opened to the public in the People’s Republic of China, it serves as a grand showcase for foreign dignitaries. The Badaling section of the Great Wall welcomed approximately 10 million visitors in 2018, and a daily visitor limit of 65,000 was introduced there in 2019. Selected as one of the ‘New Seven Wonders of the World’ on 7 July 2007, the Great Wall is a magnificent historical structure and a must-see destination.