FULING — For years the villagers didn't know what that high chimney on the verdant Jinzi Mountain, towering above the Wu River like a look-out post, was for. Turns out it's part of a huge and until relatively recently, super secret nuclear base that was dug under the mountain in Fuling, about a two-hour drive away from Chongqing, in southwest China.

In 2010, the Chinese government — after keeping a tight lid for decades on what was once one of its most ambitious military projects — opted to convert it into a tourist attraction. The base, codenamed "816 Nuclear Military Plant," remained closed for several more years while workers overhauled it. Finally, this past September, it reopened.

The dimensions of this base, which was intended to manufacture plutonium-239 for atomic bombs, are colossal — more than 1 million square feet. With its more than 20 kilometers of tunnels and 18 gigantic caves made for the reactor, the site is said to be the world's largest known network of man-made tunnels.

After crossing tall green gates surmounted by the Red Star of the Communist Party, we find ourselves taken back to the time of the Cold War, a time when Chinese nuclear ambitions were as chilling as those of North Korea today. In making this journey back in time, it's hard not to draw a parallel between Kim Jong-un's current strategy and that of Mao Zedong — the Great Helmsman — more than a half century ago.

The project was launched in 1966, only a few years after China broke with the "revisionist" Soviet Union, which had helped it develop its nuclear program. United States, in the meantime, had launched its military intervention in Vietnam. Fearing American and Russian strikes, Mao decided to bury deep in the ground a power station capable of fueling atomic weapons. It was designed to be able to withstand thousands of tons of explosives, as well as a magnitude 8 earthquake.

Incredible undertaking

The layout of the attraction was carefully designed to glorify Chinese nuclear achievements. The first highlight comes when we enter a deep, dark cave colored by neon lights that change from blue to red and white — like something you'd find in a nightclub — while grandiloquent music reverberates. A life-sized replica of the first national atomic bomb appears under the spotlights, in front of a large orange photograph of the mushroom cloud that formed after the bomb was tested in the Xinjiang Desert, in 1964.

The dimensions of this base are colossal.

More than 60,000 people — including some 20,000 soldiers and many of the country's scientists — spent time at the 816 base during its nearly two-decade construction phase. Officially, 76 soldiers, aged 21 years on average, lost their lives here, but Huang Liu suggests to the group he's guiding — most of them elderly — that the real number is higher. In fact, "several hundred" people are believed to have died here, according to various testimonies.

"The workers showed incredible courage — at the time, we did not have modern tools — and they suffered a lot. But it was to fight against U.S. imperialism," says Huang Aiguo, a pensioner, as he points to the height of the cave, nearly 80 meters.

"The soldiers were working in extremely difficult conditions, with drills, shovels and dynamite to carve the rock, which could collapse at any moment," recalls a former security officer at the site who we meet in a nearby village. "The air was unbreathable and workers, who were divided into three teams, 24 hours a day, would sometimes sleep on the spot," he adds. The security officer, now in his 60s, spent three years underground without being able to talk about his work to anyone outside.

Major money pit

In the end, all those sacrifices proved useless since the site was actually never used. Beijing, which had come to feel less threatened than in the past, decided in 1984 to abandon the project, which was 85% ready at that point. At Deng Xiaoping's instigation, priority was given to economic growth, and much of the military equipment was turned into factories. In total, an estimated $12 billion dollars was spent in vain.

"At the time, the Chinese were very poor and didn't have enough to eat. What a waste! So much sweat and blood, too!" a former civil servant who is surprisingly critical in this "red tourism" hotspot argues. And yet, the unfinished mission may at least have served to unite the participants against the foreign enemies. "Let's be vigilant, let's protect our motherland," a period propaganda poster reads.

It's hard not to draw a parallel between Kim Jong-un's current strategy and that of Mao Zedong.

This exaltation of patriotism is the first striking resemblance between Mao's approach and that of the heir of the North Korean Communist dynasty. For China in the 1950s and 1960s, the bomb was crucial to assert the identity of the young People's Republic. Similarly, North Korea's current program "aims to legitimize Kim Jong-un's regime and anchor inside people's minds the idea of a strong and technologically advanced country," says Nicola Leveringhaus, a professor at King's College in London. Both Mao and Kim, the expert goes on to say, "placed emphasis on the importance of an atomic bomb that is supposed to be developed in a self-sufficient way" the expert says — even though Pyongyang (and Beijing also, in the past) benefited from foreign contributions.

On the geopolitical level too, "both programs have the same goal: to guarantee the survival of a regime against much more powerful countries: the USSR and the United States then, the United States and China now," explains Antoine Bondaz, a researcher at the Foundation for Strategic Research. As Mao himself explained in 1956, "Without the atomic bomb, we cannot free ourselves from oppression."

China's nuclear ambitions faced fierce opposition. In December 1960, the U.S. National Intelligence Estimate believed that China's "arrogant self-confidence, revolutionary fervor, and distorted view of the world may lead Beijing to miscalculate risks." It went further and warned that "this danger would be heightened if Communist China achieved a nuclear weapons capability." Faced with this pariah state, "the United States and the USSR have considered military strikes to delay and destroy the Chinese nuclear program, both before Beijing tested its bomb and after," says Nicola Leveringhaus. Just like Donald Trump with Pyongyang today.

History as a guide?

Exasperated by Kim's sixth nuclear test in early September, China has voted in favor of tightening UN sanctions against the "hermit kingdom" (though Beijing has so far refused an embargo on oil exports). During Trump's recent visit to China, Xi Jinping, reasserted "the firm commitment" of both countries in favor of the Korean peninsula's "denuclearization."

And yet, the Communist giant, which declared in 1964 its will to break the "nuclear monopoly," strongly opposed outside controls on its own program, seeing them as a trap set by the United States and the USSR to reinforce their domination. Applying a similar logic, Pyongyang refuses to be deprived of its "deterrence" capability. But unlike Mao, Kim Jong-un, though he claims to want only to defend himself, does not hesitate to issue threats: His regime now boasts of being a nuclear power capable of "striking the whole of continental United States."

Just like Donald Trump with Pyongyang today.

Some visitors at the 816 base make the connection between the two leaders themselves. "Kim Jong-un is imitating Mao," our rebel pensioner says, growing irritated during the 90-minute tour. He believes that the dictator in Pyongyang, like the Chinese revolutionary before him, seeks only to remain in power — "without considering the interests of the people."

Tang Haihua, an energetic octogenarian who joined the project when he was 23 after attending military school, has a different opinion. He thinks that the inventor of the "Great Leap Forward" made the right choices "to fight against China's enemies." This fervent Communist is also willing to give the benefit of the doubt to the "supreme leader" of North Korea. "The entire world is conspiring against him even though he is only the head of a small country," he laments. The man also questions why America "should have the right to have nuclear power and not the others."

After a period of high tensions, the normalization of relations between China and the United States in the late 1970s facilitated the recognition of the People's Republic as a nuclear power, and Washington's fears never materialized. The future will tell whether Pyongyang — which poses a "serious threat" to the "whole world," according to the Trump administration— will be as successful as its imposing neighbor in making its presence in this very exclusive club accepted.