The Great Wall of China was declared a world heritage site in 1987 by UNESCO. The Great Wall had been diminished by human activities, such as land development, and environmental issues, such as erosion. Laws passed by the Chinese government have provided more protection for the Great Wall and more funding for its restoration.
The Great Wall of China started out not as a single, massive wall to protect the people of a unified nation, but rather as several smaller, unconnected walls that were built by warlords fighting each other. During what is known as the "Warring States Period," from 475 B.C. to 221 B.C., China had seven larger states: Chu, Qi, Wei, Yan, Zhao, Qin and Han. To protect their territories, the warlords began building walls for defense.
It wasn't until Qin Shi Huang became emperor in 220 B.C. that the sections of the wall began to be joined together to form a common defense for China, according to the United Nations. The goal of the unified wall was to defend China against Mongol invaders from the north. With this change in purpose, sections of the wall in central China became useless and were allowed to erode and fall.
The Great Wall of China represents thousands of years of work rather than the massive building project of a single emperor or even a single dynasty. After the Qin Dynasty ended in 206 B.C., construction still continued until 1279, when the Yuan dynasty took control. The Yuan dynasty was a Mongol dynasty that briefly unified the Chinese in the south with the Mongols in the north, rendering the wall unnecessary, so no further work was accomplished. When the Ming Dynasty gained power in 1368, work was restarted and continued until 1644.
The components of the Great Wall of China are more than 5,500 miles long, according to the BBC. The 2009 study by the State Administration of Cultural Heritage and the State Bureau of Surveying and Mapping found that there were almost 3,900 miles of walls, 225 miles of trenches and 1,400 miles of natural barriers to prevent foreign invasion. Before this study, the length of the Great Wall was only estimated to be about 3,100 miles long because sections that had been diminished over time were overlooked.
The best time to visit the Great Wall depends on the natural scenery that you prefer and the section of the Great Wall you plan to visit. According to China Highlights, the further north you travel, the colder and rainier the weather will be. Spring trips provide a view of fresh foliage and allow you to avoid the summer tourism season. Summer means larger crowds, but it also provides a view of blooming flowers. July and August bring the most rain. Winter brings the fewest tourists because of the cold temperatures, but the snow on the mountains can provide a stunning view.
BBC: Great Wall of China "Even Longer"
China Highlights: When Is the Best Time to Visit the Great Wall?
Kennan, Mark. "A Quick History of the Great Wall of China." Travel Tips - USA Today, https://traveltips.usatoday.com/quick-history-great-wall-china-11378.html. Accessed 23 April 2019.