The flying saucer. For decades it's been synonymous with UFO terror. But millions of reported encounters tell a very different story. From Cold War showdowns to telepathic terrors, join is as we track the rise of Black Triangles.

Millions of people believe extraterrestrial live on Earth. Are the aliens here to enlighten us or destroy us? What if the worst-case scenario happened? What would aliens do? And how would they do it?

UFOs. They can fly at blinding speed. Or hover effortlessly just a few feet above the ground. And they can do it all without making a sound. But how is this possible? The mysteries of anti-gravity propulsion are unsealed.

Nations all over the world are rumored to have recovered metal debris from these UFO crashes. From self-healing hulls to sinister alien implants, join is as the secrets of UFO metals are UNSEALED.

Do visitors to planet Earth come from some far off galaxy? Traveling vast distances to the only planet boasting intelligent life in this corner of space. We investigate the shocking secrets of alien civilizations in our solar system.

Our world is home to many UFO hot spots, where unidentified objects are reported with alarming regularity. But a select few locations have something extra. They're notorious for strange paranormal phenomenon to extraterrestrial activity.

Some experts believe many atmospheric light shows are actually caused by extraterrestrials. Do they pose an imminent threat to humanity? Join us as the alien secrets behind atmospheric anomalies.

They're our first line of defense in the darkest of times. And they're often the first responders to threats from another world. Over the past 70 years the world's military forces have come face to face with thousands of UFOs.

Every day, millions take to the sky in commercial flights all over the world. But decades of evidence have revealed we may not be the world's only frequent flyers. Are we in danger of losing control of our skies to extraterrestrial beings?

It's the ultimate close encounter. There have been thousands of reported cases all over the world. But these claims are almost invariably dismissed by authorities with little or no investigation.

The Nazis. Led by Adolf Hitler, they were the greatest evil the world has ever known. In just ten years, Hitler took Germany from crushing depression to world domination. Did the Nazis have access to alien technology?

In the 1960s we too our first steps into a vast new realm-bound for the Moon. But NASA astronauts would soon find they weren't the only ones out there.

It's the stuff of nightmares. Emergency lines flooded with calls as UFOs appear in the sky. Mounting evidence has revealed that UFO waves are able to penetrate the world's most closely guarded airspace.

Experts have long believed the universe to be riddled with mysterious portals - shortcuts through space that allow travelers to span vast distances in the blink of an eye. From mighty volcanoes to secret underground civilizations.

What are UFOs? Are they spacecraft? Do they travel vast distances to reach planet Earth? From mysterious planets at the edge of the Solar System, to epic journeys beyond the boundaries of time and space.

Do aliens exist? And have they visited planet Earth? These are perhaps the most important questions of our time. For decades, eyewitnesses have come forward with unsettling stories of alien bodies recovered from crashed UFOs.

Many believe aliens are already here on Earth. But why are they here? Are aliens planning an all-out attack on planet Earth? And if they are, is there any way we can fight back?

Nearly three hundred million people worldwide claim to have been abducted by aliens. Many report being subjected to torturous medical experiments. Others return with unwelcome reminders of their ordeal. Are aliens creating human hybrids?

For decades, UFO researchers have demanded that the government reveals what is knows about UFOs. Who will make the announcement? When will they do it? And what will it mean for the very bedrock institutions of society?

It can happen to anyone at anytime; a close encounter with a UFO. Citizens all over the world have been reporting incidents with alarming increase. We are counting down the top ten civilian close encounters of all time.