Area 51 becomes a symbol of secrecy within the U.S. military-intelligence system.

China's Roswell. Legends from China tell of 716 mysterious stone discs, known as "The Dropa Stones". Some believe the stones hold secrets about ancient contact with extraterrestrials. Discovered in a cave in 1938, each 12" disc contains a double spiral of tiny hieroglyphs that are said to contain the historical record of an alien race called the Dropa that crash-landed in an isolated region of China 12,000 years ago. The story of the Dropa Stones is an amazing tale filled with mystery, deceit, and conspiracy, and today, skeptics and true believers wage an ongoing battle over what they are, what they mean, and if they even exist at all. Regardless, the Dropa Stones continue to consume the imaginations of scientists, journalists, historians, UFO buffs, and stargazers in general.

The phenomenon of alien abduction is reviewed. Hypnotic regression is conducted and an alleged implant is removed.

A review of what some say is evidence of UFO encounters through mankind's history – from prehistoric cave paintings, to Medieval frescoes, to Renaissance art that depict strange objects in the sky.

Researchers reinterpret religious documents to find evidence of ancient UFO activity.

The puzzling formations known as crop circles have appeared worldwide throughout history. In the Middle Ages, they were called "witch" or "pixie" circles, and a 1678 woodcut, the "Mowing Devil", depicts one thought to be Satan's work. But in the 1980s, the phenomenon escalated, with dozens of crop circles popping up in England and other countries. When two Englishmen claimed they had perpetrated the hoax, many felt the riddle was solved. And yet, more have materialized. We explore the mystery.

Since the 1960s, thousands of UFO landings, flyovers and collisions have left scientific evidence behind for study. These events have become known in the field of UFOlogy as the "trace cases." There are over 3,000 documented UFO physical trace cases and they have occurred in over 90 countries around the world. From impressions in the dirt, burned or broken vegetation and trees to scientific abnormalities that have yet to be explained, trace cases offer up some of the most convincing evidence of the UFO reality.

A rancher's nightmare, the mysterious murder of livestock has plagued farmlands worldwide for generations. Commonly known as cattle mutilations, these bizarre deaths happen to horses, goats, sheep, rabbits, and others, though the most frequent victims are cattle. Most often, udders, ears, tongues, and eyes are somehow surgically removed from the animal without spilling a drop of blood! We explore the prevailing belief that extraterrestrial beings bear responsibility for these grotesque, bloodless slaughters. Alien presence provides an explanation for the manner of killings and the ability to perform the delicate operation so consistently and so precisely. Viewers will watch an actual field investigation unfold as we delve into the history of the cattle mutilation phenomenon and its connection to UFOs.

In 1947, a strange object fell from the sky near Roswell, New Mexico, and controversy brewed over what it really was. In November 2001, we convened a team of experts at the National Archives for an exclusive first look at the top-secret government files of the UFO incident. We unveil the remaining classified files--11 boxes with 17 notebooks of declassified files, photos, transcripts and audiotapes of dozens of witnesses, and 22 films and videos--in a definitive statement on the 50-year-old mystery.

Studies some of the most disturbing UFO sightings, including: a 4-day extravaganza in 1952, when UFOs cruised the skies over the White House; sightings in 1967 near a secret US/Canadian submarine detection base; controversial events at the UK/US air base at Bentwaters, England; and the military's Test Area 51 in Nevada. Recounts the recorded UFO encounters that have taken place near test ranges, air bases and nuclear power plants. Included: a widely reported July 1952 sighting over Washington, D.C. Also: the secret world of Area 51.

It's all hush-hush as we track a secretive global paper trail, delving into government plans on how to deal with other-planet visitors. Searching historical records, we find that protocols are in place--from the U.S. military's JANAP-146 reporting requirements to France's Cometa files, from Chapter 13 of the FEMA Fire Officer's Guide to Disaster Control titled "Enemy Attack and UFO Potential", to a now-repealed federal law titled "Extraterrestrial Exposure".

In an investigation of some of the most puzzling UFO sightings in Soviet history, we uncover the work of an underground network of believers and reveal a clandestine 13-year government investigation of UFOs. Many Russian UFO enthusiasts believe that proof of alien encounters exists--but it's being hidden from them! We also meet George Knapp, an American broadcast journalist who traveled to Russia in the early 1990s and believes there's a treasure trove of KGB UFO files that remain top-secret.

UFO Files examines the most debatable aspect of alien contact--human abduction! From the first recorded case, the 1961 kidnapping of Betty and Barney Hill, to the 1976 Allagash Incident, when four friends were whisked away while on a camping trip, we hear firsthand from participants and a neuroscientist, who offers more earthbound solutions.

For those who study the UFO phenomenon, "UFO Hot Spots" are places around the globe known for a long history of UFO sightings and reports. From Brazil to Mexico, from Washington State to Florida, multiple witnesses, including air traffic controllers and even military personnel, confirm that something unexplained is repeatedly happening in the night sky. Tales of alien abductions, bizarre and chilling photographs of UFOs, and hours of videotape all abound as we search for UFO Hot Spots.

Investigation into the 1991 mass UFO sighting over Mexico City during a solar eclipse and other sightings as possible examples of alien contact with the inhabitants of planet Earth.

An examination recently declassified documents in the CIA archives, in an attempt to uncover a half-century of suppressed, distorted, and even fabricated reports of UFO sightings.