The Great Wall of China is one of the most iconic monuments in the world. It is a series of fortifications built to protect the Chinese Empire against invaders from the north and west. Construction of the wall is believed to have begun as early as the 7th century BCE during the rule of the States of Qin and Western Zhou Dynasties. Over the centuries, the wall has been rebuilt, repaired and extended. By the time of the Ming Dynasty (1368-1644), the Great Wall had reached its present form, stretching more than 6,000 kilometers from east to west.
Different sections of the wall were built at different times. The first phase of construction began under the rule of the Qin Dynasty (221 – 207 BCE). During this period the original 600-kilometer wall was built in northern China. This included portions of the wall in Inner Mongolia, Shanxi, Hebei, Shaanxi and Ningxia.
By the time of the Western Han Dynasty (206 BCE -9 CE), the wall had been extended to an estimated 3,200 kilometers, reaching as far west as Jiayu pass in Gansu Province. Much of the existing structure dates back to this time period. During this period, watchtowers and barracks were also added to the wall.
The period of the Sui Dynasty (581-618) saw further extension of the Great Wall. Additional fortifications were built using a variety of materials, such as stone, soil and rammed earth. This increased the length of the wall to approximately 5,000 kilometers.
The Northern Qi Dynasty (550-577) and the Northern Zhou Dynasty (567-581) also contributed to the development of the Great Wall by connecting walls in the south with the wall in the north. This is how it acquired its current form.
During the Ming Dynasty (1368-1644), the Great Wall was further strengthened and renovated. This included adding additional fortifications and defensive structures, such as cannon towers, watchtowers and barracks.
Although the wall has endured for centuries, much of it has fallen into disrepair over time. Since the 1950s, restoration and repair work has been carried out on various sections of the wall. In 1987, the Great Wall was designated a UNESCO World Heritage Site.