Soviet leader Joseph Stalin concealed Hitler’s body from the West for decades. The FBI spent years tracking false leads and sightings of Hitler. Only in the 1990s did Russians open archives to reveal a handful of Hitler's teeth and fractured skull pieces.

Police closed the case of the infamous Boston Strangler when Albert De Salvo confessed to the grisly murder of 13 women. But recent forensic evidence reveals the Strangler could still be at large.

In 1918 Russia's last imperial dynasty, the Romanovs, were assassinated. But doubts remain as to whether all members of the royal family were put to death. Did the Tsar's daughter, Anastasia, escape?

On July 8, 1947, the U.S. Army issued a press statement claiming to have recovered a flying saucer on a ranch outside Roswell, New Mexico. But within hours they retracted the statement saying they had only found the remains of a weather balloon. Sixty years later the debate still rages and Roswell has become the UFO capital of the world. Did the military really recover dead aliens and their spaceship, as some people claim?

For 20 years, FBI Director J. Edgar Hoover denied the existence of the mafia. Was it because he was being blackmailed by them, with the threat of being exposed as a gambler and cross-dresser?

As world famous aviator Amelia Earhart closed in on her record-setting attempt to fly around the world in July 1937, she disappeared somewhere over the Pacific Ocean - vanishing without a trace. Did she run out of fuel and crash into the sea? Or could she have survived? NGC explores one of the most fiercely debated mysteries of all time. Investigators build the case that she was a pawn in an espionage plot for President Franklin D. Roosevelt, while eyewitnesses testify she was captured by the Japanese military. Examine the evidence and decide for yourself what might have happened to Amelia Earhart.

How and why did a man so rich, so accomplished and so visible become so reclusive, phobic and fragile? How much truth is there in the popular image of Hughes' descent into madness? What can recent medical discoveries contribute to our understanding of this man, his habits, behaviors and final years? NGC reviews recent studies of America's most bizarre billionaire.

Ted Kaczynski sent the FBI on a $50 million manhunt. We investigate how his childhood as a prodigy led him to academic glory at Harvard.

Neil Armstrong, the 1st human being to set foot on another planet. We bring you the the untold stories of Apollo 11's mission and the 5 moon landings.

A US army scientist died for his involvement in a secret CIA experiment.What was the true extent of these secret CIA experiments and their casualties?

NGC delves into the tumultuous history of the atom bomb - filled with deception, twists and danger that even Hollywood couldn't make up. Culling from rarely seen archival footage and interviews with leading experts, we'll see how Soviet spies gathered top-secret information during WWII. Learn why China shared its nuclear weapons technology with other countries. Find out how Israel's nuclear weapons program was exposed by a disgruntled worker who leaked information before being kidnapped.

Documentary exploring the remarkable escape of three prisoners from the fortress-like penitentiary in 1962, and the still-ongoing US Marshals investigation to track them down.

Charles Lindbergh becomes the world’s most famous man in 1927 when he flies non-stop from New York to Paris. But behind the legend was a man who juggled multiple secret lovers and took on a President.

Seven years after a deadly anthrax attack in the US, the FBI announces a suspect. But the man committed suicide just days before being accused. Is he a scapegoat in a case that will never be solved?

There's more to Abraham Lincoln than meets the eye. Far from a simple lawyer who freed the slaves, Lincoln is actually a shrewd manipulator. Explore his hidden political and strategic genius.

July 1947,some remnants of a strange object were found in Roswell. Rumoured to be UFO but authorities deny it. Are they hiding something?

How could a man, so rich, famous and visible for so long, become an isolated recluse? Recent medical studies shed new light on the life and death of one of America's most intriguing billionaires.

More than 20 years after army scientist Dr Frank Olson falls to his death from a hotel window in 1953, the US government reveals he was involved in secret experiments studying LSD and interrogation.

Maths whiz and child prodigy, Ted Kaczynski found academic glory at Harvard by the age of 16 but strange and dangerous stress tests he took here may have influenced his later rampage which killed 3.

24 astronauts ventured to the moon on a single engine with the Apollo missions. These are the untold stories of NASA's rarely-remembered breakthroughs, harrowing escapes and heartbreaking disasters.

Seven years after a deadly anthrax attack in the US, the FBI announces a suspect. But the man committed suicide just days before being accused. Is he a scapegoat in a case that will never be solved?

In 1971 a hijacker in a business suit leaps from a plane with a parachute and US$200,000 in ransom money, never to be seen again. Now a team of citizen sleuths helps the FBI unravel the mystery.

Charles Lindbergh becomes the world’s most famous man in 1927 when he flies non-stop from New York to Paris. But behind the legend was a man who juggled multiple secret lovers and took on a President.

Since the detonation of the first atomic bomb, nuclear weapons have spread from major nations to small countries and terrorist groups through espionage, double-dealing and covert plots.

There's more to Abraham Lincoln than meets the eye. Far from a simple lawyer who freed the slaves, Lincoln is actually a shrewd manipulator. Explore his hidden political and strategic genius.