Hidden inside the world's castles and mansions are secrets waiting to be revealed. What remarkable tales of mystery and adventure transpired within their walls?

Could there be life beyond our planet? Extraordinary NASA footage and ground-breaking interviews with astronauts and scientists investigate potential sightings of UFOs.

Could there be life beyond our planet? Extraordinary NASA footage and ground-breaking interviews with astronauts and scientists investigate potential sightings of UFOs.

Former Colorado law enforcement officer Chuck Zukowski and his son Daniel investigate UFO-related cases that the authorities usually ignore. They search for definitive proof of UFOs along America’s infamous Alien Highway.

Former Colorado law enforcement officer Chuck Zukowski and his son Daniel investigate UFO-related cases that the authorities usually ignore. They search for definitive proof of UFOs along America’s infamous Alien Highway.

Don Wildman investigates the "Crime of the Century," examines a miniature human head from South America and looks at a reptilian cryptid.

Experts and eyewitnesses try to unlock the mystery of the Alaska Triangle, a remote area infamous for alien abductions, Bigfoot sightings and paranormal phenomena.

Paranormal explorer Dakota Laden takes his sister and best friend on a cross-country road trip to face their fears at the most haunted locations in America.

On The Dead Files, physical medium Amy Allan and retired NYPD homicide detective Steve DiSchiavi combine their unique and often conflicting skills to solve unexplained paranormal phenomena in haunted locations across America.

On The Dead Files, physical medium Amy Allan and retired NYPD homicide detective Steve DiSchiavi combine their unique and often conflicting skills to solve unexplained paranormal phenomena in haunted locations across America.

The Holzer Files is an American paranormal television series following a team of ghost hunters as they investigate cases documented by the late Hans Holser.

Don Wildman uncovers the secret behind perfectly preserved mummies in Mexico. Plus, he investigates the world's most-famous UFO conspiracy.

On the outskirts of Anaconda, Mont., sits Gunslinger Gulch -- a sprawling ghost town and guest ranch made up of various historic abandoned buildings salvaged from across the state

They may be known as the first family of darkness, but legendary rocker Ozzy Osbourne and his wife, Sharon Osbourne, are borderline skeptics when it comes to the paranormal. Determined to convert his parents into full-fledged believers, Jack Osbourne shares the craziest, most jaw-dropping supernatural activity ever caught on camera.

Police officers, paramedics and other first responders reveal their true encounters with the paranormal while on duty. Not only do these cases defy explanation, they terrify even the most seasoned of men and women who have devoted their lives to serve and protect the living.

The Holzer Files is an American paranormal television series following a team of ghost hunters as they investigate cases documented by the late Hans Holser.

Experts and eyewitnesses try to unlock the mystery of the Alaska Triangle, a remote area infamous for alien abductions, Bigfoot sightings and paranormal phenomena.