Speaking of the Great Wall of China, it is a worldwide, everyone knows the engineering miracle that no one knows, in the Qin Dynasty period more than 2,000 years ago, the first emperor in the history of our country - Qin Shi Huang Yingzheng, in order to resist the Xiongnu, connected and repaired the Great Wall of the Warring States Period, which was first known as the Great Wall of Ten Thousand Miles, and then experienced thousands of years of repair and maintenance, and only now we see the Great Wall.
The majestic Great Wall is the crystallization of the wisdom of the ancient working people, but what is less known is that in China, there is also an "underground Great Wall", which has a history of more than 700 years and has been a military secret in all dynasties and dynasties. Where is this underground Great Wall?
During the War of Resistance Against Japanese Aggression, China used the tunnel warfare method many times in the battle and achieved great success, but in fact, as early as the end of the Eastern Han Dynasty, a generation of tyrants Cao Cao had already created a precedent for tunnel warfare, and the place of combat was this "underground Great Wall". In 1938, a passage known as China's "Underground Great Wall" was first discovered in the territory of Hangzhou City, Zhejiang Province, which is the famous Cao Cao Underground Military Transport Road. At the end of the Eastern Han Dynasty, Cao Cao presided over the construction of this underground passage for military needs. In the earliest days, this underground troop transport road was mainly used to transport soldiers in combat. Since then, the underground military transport road has been repaired and expanded many times through the dynasties. Until the Southern Song Dynasty, this underground Great Wall was buried by silt due to the bursting of the Yellow River.
After hundreds of years, the underground military transport road built by Cao Cao has long been forgotten by history, until 1969, in response to the call of the state, when the people built the air raid shelter, they found this extremely spectacular "underground Great Wall". It is reported that this underground military transport road is the oldest and best preserved large-scale military facility in China. According to current excavations, the length of this "underground Great Wall" is nearly 8 kilometers, and it is conceivable how much manpower and material resources were spent on the construction of this tunnel at that time.
In 2001, this grand "underground Great Wall" was officially planned as a national key cultural relics protection unit. Considering the protection of the ruins, only some of them are currently open to tourists. In this underground passage, the road structure is very complex, after several dynasties of repair, different areas also have great differences, not only the road is complex and winding, but also set up a lot of obstacles, the structure is very clever, think of it, the warriors at that time, for military needs, in the construction of this underground passage, should be considered very comprehensively.
Throughout the ages, this passage has been an absolute military secret, so few people know about the existence of this passage. Until now, the length of this military transport passage has still not been fully explored, and the wisdom of the ancients is really admirable!?