On May 17, 1968, the nuclear submarine USS Scorpion was making her way through the Mediterranean returning to base at Norfolk, Virginia, when she received top-secret orders to report on a mysterious group of Soviet warships and submarines lurking around the Azores. On May 21, the Scorpion completed her mission and signaled her return. But she never arrived back to base. Though the wreckage of the 3,000-ton submarine was later found, it revealed few clues to its demise.

In January 1974, the Gaul, a deep-sea trawler, slipped out of harbor in northeast England. By February 7, the Gaul had caught and packed nearly 20 tons of fish in the Barents Sea. When bad weather closed in and the Gaul was battered by gale-force winds and high seas, the skipper sent two radio messages--the last heard from the Gaul. The trawler and 36 men had vanished! Built to withstand inclement conditions, why did she disappear? Why was there still a mystery 20 years after her disappearance?

On January 4, 1910, the wooden steamship SS Farallon left port in Alaska, heading south along the coast. While crossing the treacherous Cook Inlet, the ship stuck fast on a reef of jagged rock. In the middle of the winter, the crew and passengers had no choice but to abandon ship and make for the deserted, rocky shoreline. Stranded without radio contact and not expected in port for a month, as far as the world was concerned, the 29 officers and nine passengers had vanished without a trace.

On January 29, 1982, Steven Callahan, sailing alone, slipped out El Hierro, the smallest of the Canary Islands. The 29-year-old American planned to reach Antigua by February 25. Six days after leaving port, Callahan was caught in a raging storm during the night. As his boat was being battered, he cut his life raft free just in time. But he didn't have time to send a distress signal--and he was adrift 450 miles from the nearest land. To the outside world, he had seemingly vanished without a trace.

On October 28, 1991, Hurricane Grace battered the entire eastern Atlantic seaboard with winds reaching 95 mph. But the worst was yet to come when Grace collided with a cold front from Canada and a storm from the Great Lakes. And somewhere, 400 miles offshore, a sword-fishing boat named the Andrea Gail was heading home with a hold full of fish when she found herself at the center of the so-called "Perfect Storm"--and was never seen again.

On July 11, 1980, the British bulk carrier The Derbyshire set sail from Canada for an 11,000-mile voyage to Japan. On September 9th, just days before the ship was due in Japan, it unexpectedly was caught in the full fury of a tropical storm. The skipper sent a position report to Liverpool and contacted a ship about 80 miles astern. It was the last time anyone heard from The Derbyshire. The Derbyshire wasn't the only bulk carrier to vanish. Was a storm the cause of her disappearance or something else?

On September 29, 1918, U.S. Lieutenant Frank Luke took off in his biplane from a field in France and headed for the frontline 11 miles away. His mission--to destroy three German observation balloons. Balloon busting was a highly risky task, and Luke was reckoned to be the best. In just over two weeks, he destroyed 14 enemy balloons. After exploding his last three balloons, Luke vanished. We reveal what happened to the brilliant young flyer and posthumous recipient of the Congressional Medal of Honor.

In 1938, Douglas Corrigan climbed into his single-engine monoplane for a nonstop flight from New York to Los Angeles. But puzzled onlookers witnessed his plane make a 180-degree turn and head into a bank of fog--in the wrong direction! When Corrigan reappeared in Ireland the next day, he maintained that he'd "accidentally" achieved his dream of flying across the Atlantic--a flight forbidden him by authorities. Was he unfairly elected an honorary member of the Liar's Club of America?

The story of one of Great Britain's greatest and best-known WWI flying aces, 21-year-old Albert Ball, who vanished without a trace during a dogfight with six German planes. On May 7, 1917, Captain Ball took off in his fighter plane from a base in France headed to the frontline. He and his flight group spotted a British plane under attack by two German planes and joined the fray--along with four more German planes! Finally, Ball and the last German plane disappeared into a cloud--still firing their guns.

On the morning of August 16, 1942, residents of Daly City, near San Francisco, were astonished to see a U.S. Navy airship drifting aimlessly overhead. Within a few minutes, the rapidly deflating dirigible came down at a road intersection and was immediately surrounded by fire crews, police, and curious spectators. Apart from the door, which hung open, inside the cabin everything seemed in order. But the 2-man crew was missing without a trace, and their fate remains a mystery to this day.

In October 1972, a rugby team and friends en route from Uruguay to Chile boarded a plane in Argentina for a 90-minute flight to Santiago. They never arrived. The plane's route over the Andes was searched for weeks, but there was no trace of the aircraft. But 72 days later, two survivors walked out of the Andes. Rescue helicopters found 14 more stranded in the mountains. They had survived by living inside the wrecked fuselage--and eating the flesh of their dead companions! This is their story.

Early on the morning of June 15, 1955, a distinguished state judge, 58-year-old Eugene Chillingworth, and his wife went missing from their home in a Florida beach resort. They were never found. Judge Chillingworth had one enemy--a colleague on the legal circuit, Judge Peel. Chillingworth had been keeping close watch over Peel's business interests and was about to reveal illegal dealings. We see how, when police took notice, Peel's paid henchmen confessed to murdering and disposing of the Chillingworths.

Shortly after 8:30 p.m. on February 8, 1983, a gang of masked men burst onto an Irish stud farm. They had come to steal Shergar, one of the most celebrated racehorses in the world. A nationwide police hunt for Shergar and his kidnappers was soon under way, but to no avail. The champion racehorse had vanished without a trace. We follow police efforts to locate Shergar and investigate the theory that the IRA took Shergar in the hope of recovering an enormous ransom.

On November 18, 1961, 23-year-old Michael Rockefeller set out from a missionary outpost to visit remote villages deep in the interior of Papua, New Guinea. He never made it back to shore. When his native catamaran was swamped in rough seas, Michael decided to swim for help--he was never seen again. Nelson Rockefeller, Michael's father and New York's Governor, coordinated an extensive search, but no remains were found. Did Michael drown or meet a gruesome fate at the hands of headhunters?

On November 6, 1935, Sir Charles Kingsford Smith took off from an airport near London in a Lockheed Altair monoplane, the Lady Southern Cross. The Australian, one of the world's best-known pilots, was determined to win back the England-to-Australia air speed record from an English rival who had broken his record in 1934. Due in Singapore on November 8, Kingsford Smith had vanished without a trace. But when an aircraft wheel was found 19 months later, new clues emerged to add to the mystery.

One of Southeast Asia's most successful and best-known entrepreneurs, Jim Thompson spent 20 years building up his Thai silk business. On Easter Sunday 1967, the 61-year-old silk magnate went for a walk in the Cameron Heights of Central Malaysia--and was never seen again! A full-scale search was mounted the next morning, and two days later, more than 400 people looked for him, but not a clue was found. Was he kidnapped by tribesmen, mauled by wild animals, or did he fall foul of the Triad gangs?