This is a part of declassified historical data—the mysterious project “6501” comes from document No. 1 of the Central Military Commission of the Communist Party of China (CCP) led by Vice Premier and Minister of National Defense Lin Biao promulgated in 1965. This vast underground project cost over $86 million (600 million yuan), was secretly built by the military, and was dubbed the mysterious “Underground Great Wall of China.” Recent reports have revealed the mystery of this massive man-made structure.

According to Sina, the giant cave named “6501” is located in Zhongfang, Linxiang, Hunan. The main door is almost 40 feet (12 m) wide by 40 feet high, with a very complex cave structure. There are 25 halls and 17 ventilation holes, with a total length of more than 10.5 miles, the large hole is designed for trains, and the small hole is designed for trucks. In addition, there are 18 circular concrete platforms where 18 large oil tanks were initially located. Therefore, it is known to the outside world as “China’s Underground Great Wall.”

Since 1965, special project “6501” was under construction in extreme secrecy for eight years. Then, at the beginning of 1973, it was suddenly abandoned, and no one knew its function, role, or the reason for its construction. In recent years, the local authority has developed an “artificial desert” in the middle of the area. The Taolin lead and zinc mine are almost two miles from the desert and are promoted as a tourist attraction.

This nearly 40-year-old underground defense work has been attracting more and more attention from the outside world since it was developed as a tourist attraction. As a result, it became the focus of public opinion in the northern region of Hunan.

The mystery of ‘The Underground Great Wall of China’

Project 6501 is over 9 miles from Linxiang town. Linxiang is the northern gateway of Hunan province, under the jurisdiction of Yueyang. It is about 96 miles from Wuhan and 100 miles from Changsha. It takes about 5 minutes to go down the Linxiang gateway from the Beijing—Zhuhai Expressway. The river named Chang’an flows through the town.

According to reports, cold air that flows from the cave can be felt hundreds of meters from the entrance of this vast project. When entering the “6501” cave, a black net covering nearly half of the cave entrance can be seen.

Judging from the available information, Project 6501 comes from document No. 1 of the Central Military Commission of China in 1965. It is also the largest known man-made military cave in China.

It is divided into upper, middle, and lower layers. The entire mountain is hollow, connecting the top and bottom. Entering the cave for the first time is like entering a maze. The granite structure of the giant mountain is hollowed out, and the upper and lower floors are fortified with reinforced concrete. The year-round temperature in the cold and humid cave is about 64.4°F (18°C).

Surprisingly, in addition to the 10-plus-mile-long artificial cave, Project 6501 consists of 25 large and small caves, the most prominent place are up to hundreds of square yards, and there are 17 large rocket-shaped caves. The purpose of the caves seems to be to command, assemble weapons and store ammunition. The rocket-shaped cave is over 262 feet high, from 32 ft to 64 ft in diameter, looking like it’s going straight to the top of the mountain.

The discovery of the base was accidental

In the early 1980s, a farmer was grazing his cattle when suddenly his cattle got lost. He looked around and heard the cattle sound from the cave. He found a rope and used it to climb into the cave. Going deeper, he saw a man-made structure resembling a labyrinth.

As the news spread, adventurers and treasure hunters from all walks of life flocked there.

The mystery of this vast man-made construction has attracted many people. After that, some treasure hunters picked up the cave’s steel bars and iron doors. Most metal products were sent to large and small garbage collection stations.

According to Du Wenxiang, a local who year-round watches the mysterious project “6501”, the stolen items had a market value of more than $431,000 (3 million yuan) at the time. In addition, much equipment and steel rod in the cave was stolen, causing the local authorities to panic. However, the police were then involved, the theft subsided, and the special project 6501 was gradually protected.

The secret facility built by Lin Biao

What kind of project is this? How is it built? What is it built for?

Zeng Zhongmin, an employee who had been stationed all year round at project 6501, said that according to the information they had, the engineer soldiers who built 6501 at that time would have gathered on a stuffy tank truck at a nearby mining station and then drive into the construction site at night.

Keeping the confidentiality of project 6501 was a top priority from the moment of beginning construction to its abandonment. Unfortunately, as a result, local people and even local authorities are unaware of this project.

Zeng Trung Dan said that after a few mountain residents moved out, the military cordoned off nearby mountainous areas. These builders were there for eight years and didn’t know what and where they were building, nor could they tell if there were other similar projects in the area.

Xiao Hesheng, a resident, shared that he saw substantial oil barrels in the cave then. He said: “Back then, the large oil pipeline was refined and built to Daliankou near 6501, but if you look closely, the whole design of the cave is completely different from the layout of the refinery.”

“When work was suspended, I went to the cave to observe. The project must be half done!.” Xiao vaguely remembers that the project had been suspended since 1972, and by early 1973, all had been evacuated.

Judging from the partially declassified historical data, the person who issued the order to build the “6501” project must have been Lin Biao. At that time, he was vice chairman of the Central Military Commission of the CCP. Therefore, the specific operator of the project must be Huang Yongsheng, then the Commander of the Guangzhou Military Region.

Why is “6501” suddenly withdrawn? One clue is that Lin Biao, who signed off the building order “6501,” died in a plane crash in Undur Khan, Mongolia, on September 13, 1971.

One of the most popular stories about project 6501 is that this project invested more than $86 million at that time. The special project took place for eight years and stopped due to the “September 13, Lin Biao” incident.

Resident Yu Wenxiang said: “This place is very mysterious because it is the center of Hunan, Hubei and Jiangxi, which is also the battlefield of military strategists. The geological conditions are good with natural granite, a water source and surrounded by mountains, so it is easy to be hidden and camouflaged.”

A missile base or an oil refinery?

Today, Project 6501 has three underground floors, but only one is open to the public. The outside world speculates that this place was used to launch rockets.

Some visiting scholars believe that 6501 is located at the confluence of Hunan, Jiangxi, and Hubei, so it has a highly favorable geographical position. Some also talked about the historical context, such as the three-year difficult economic period, the Sino-Indian border counterattack, the tense Sino-Soviet relationship, the events of “September 13, etc.

The most important thing was that at that time, artillery shells hit the southern area not far from the China-Vietnam border. In addition, an essential international ally of China, the Soviet Union, no longer had a tight relationship with China. Therefore, at that time, “It was suggested by Lin Biao and approved by Mao Zedong that it was necessary to “prepare for war and famine.”

These rumors lead to a long list of conjectures that appear to be of cause and effect.

In addition, there are many slogans in the cave, such as “grasping the revolution, boosting production, promoting war readiness,” etc., along with the specific context of the times, such as substantial investment budgets, reinforced cement concrete, raw steel reinforcement imported from the Soviet Union, black sand against moisture, and military rubber. It is rumored that this building is a place to store items dug up to prepare for famine.

This conjecture seems unreasonable. If only to store rice, why build such a high yard? The reasons for this are currently unknown.

The most grounded claim is that Lin Biao built this tunnel, but its purpose was only to build an underground oil refinery to serve the needs of the war.

A Linxiang government official, who did not wish to be named, said: “It has not been fully declassified yet. According to available information, project 6501 was China’s largest unfinished military project at that time.”

Project “6501” employee, Zeng Zhongmin, shared detail about receiving a visiting veteran. The veteran said that after arriving, he realized that this was the place where he had fought. However, at that time, he did not know which province he was in and what the building was built for.

The veteran used to look for tombstones near the 6501 project. But, unfortunately, his old close comrade died of illness during the building work and was buried here.

Finally, the veteran feels frustrated, saying: “It’s been so long that time and memory may be buried forever underground.”

Perhaps Linxiang has received attention since then and now becomes the target of location selection.

Mountains were opened, and rocks were dug to make caves. The railway from Taolin lead zinc mine not far from Linxiang dam is connected to the railway just below the cave. Today, the railway is dismantled.

Residents Yu Wenxian said that because it was in the Cold War period, this project was named Project “6501,” a secret military project at that time.

At that time, the construction team under the Ministry of Oil and Gas participating in the project’s construction was also known as “6501”. This team and Daqing Refinery Construction Company rushed to build the Changjiang Oil Refinery Company. These two units were merged to form the current Sinopec 4 digital construction company.

Next, some experts have ventured to advise that: building an oil refinery in such a vast cave can cause landslides of varying degrees at any time. The oil refining process will also generate a large amount of highly toxic gas, which is difficult to discharge. The ventilation system in the cave is not guaranteed, which is why a slight leak will cause incalculable consequences.

Even more frightening is that oil refining is an industry with a high risk of fire and explosion. Being produced in such a closed environment results in difficulties in ensuring safety. With just a little glitch, it will most likely cause a series of explosions, refining oil in the cave is like a ticking time bomb.

The project was abandoned in the mountains

Some Hong Kong media commented that this was a fantastic find. A vast and mysterious military project like “China’s Underground Great Wall” started construction in 1965 and was abandoned in 1973. It cost over $86 million. It was a construction intended to “prepare the people for war and famine” at the time. The so-called secret work put forth by Lin Biao was concealed under the banner of Anti-Revisionism, and it was only the shameful outcome of the internal struggle between Mao and Lin. Such a shady building from Mao’s time was hidden for 50 years. Now it has been developed into a public tourist area. No one cares about the historical truth; the absurdity and ignorance of this country are unbelievable.

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