A SECRET underground facility has been at the heart of one of the wildest alien conspiracies in America, and believers say it’s still active.

For nearly 50 years, the base has been tied to chilling claims of genetic experiments, UFOs, and a deadly firefight between aliens and humans.

Some conspiracy theorists say the government is hiding a war that broke out after workers accidentally drilled into an alien domain.

They believe the hidden base is located inside Archuleta Mesa, near the remote town of Dulce, New Mexico.

The area has been dubbed “Alien Mountain” by locals who claim to have seen strange creatures, glowing crafts, and mutilated cattle.

Although no hard evidence has ever confirmed the existence of a facility inside the mesa, researchers and residents remain convinced it’s real.

“The whole town of Dulce, whoever you want to talk to, they’ll tell you what they’ve seen, a lot of them,” resident Geraldine Julian told the Santa Fe New Mexican in 2016.

She said she once saw a creature with the lower half of a goat and the upper body of a human, a supposed product of an alien experimentation.

Other locals say they have seen steam rising from the mountain, and even claim to have photos of UFOs flying nearby.

Dory Vigil, who snapped one of the eerie photos, said he would take a lie detector test to prove he is telling the truth.

“It’s not just a fairy tale,” Julian said.

“All the things are true, and I believe every last one of them, too, because I’ve seen it myself.”

Much of the modern conspiracy theory centers around author, ex-government employee, and conspiracy theorist Phil Schneider, who claimed he helped build the base, per the Daily Mail.

Schneider, who died in 1996, alleged that during construction, his team accidentally breached an alien section and triggered a deadly shootout underground.

He said 66 people were killed, including military personnel and scientists, and showed off missing fingers as proof of his injuries.

He also described a seven-level facility with sections devoted to alien housing, mind control, and advanced tech.

Before his death, Schneider toured UFO conventions with a piece of metal he said came from the base, allegedly used today in stealth aircraft.

While skeptics dismissed him, newly declassified documents have sparked fresh interest in whether such a base could be real.

Government records show that in the 1970s, scientists at Los Alamos National Laboratory developed a nuclear-powered tunneling machine called the Subterrene.

The device was designed to melt rock and carve smooth tunnels underground.

Los Alamos is located just 100 miles from Dulce.

Though there’s no official record linking the Subterrene to the mesa, conspiracy research says it shows the tech may have existed to build such a base.

The first rumors began in the mid-1970s, when New Mexico State Police officer Gabe Valdez investigated mutilated cattle near the area.

He and others believed the animal deaths were not natural, and the theories about an underground facility only grew from there.

Years later, a mix of strange sightings, government tech, and eerie testimony has kept the legend of the Dulce Base alive and far from settled.