All around the world are examples of physical evidence suggesting humans are not alone in the universe, but has this evidence been left behind for a purpose? Is it a series of clues we are meant to decipher? Giorgio A Tsoukalos investigates.

After tracking Hitler's attempts to return to power through wealthy supporters in Argentina and Brazil, Bob Baer and Dr. John Cencich hit the ground in South America to tackle their biggest lead yet.

Mining the earth for coal, erecting drilling rigs for oil and natural gas to pipe to our homes, smelting iron ore into buildings of iron and steel - all of these are fundamentals of the modern industrialised world, but they are nothing new.

Host Bobby Bognar crisscrosses the country to reveal what's behind a pancake breakfast. He gets fresh with a cow in a quest to learn if there really is butter in buttermilk pancakes.

UFOs are the biggest mystery of our time and somebody - or something - seems determined to keep it that way.

The confluence of two geological forces created and continues to build the island of Iceland. They also keep the geology active with global implications. For now the massive, but retreating, glaciers are keeping the glaciers in check.

For more than 500 years, Rome was the most powerful and advanced civilisation the world had ever known, built by an unprecedented mastery of engineering and labour.

All around the world are examples of physical evidence suggesting humans are not alone in the universe, but has this evidence been left behind for a purpose? Is it a series of clues we are meant to decipher? Giorgio A Tsoukalos investigates.

Ancient Top 10

From the riddles of the Sphinx to mummification and the pyramids, Egypt has seen some of the highest-profile archaeological finds in history. But with so many contenders, which secret has had the biggest impact on our view of Ancient Egypt?

After tracking Hitler's attempts to return to power through wealthy supporters in Argentina and Brazil, Bob Baer and Dr. John Cencich hit the ground in South America to tackle their biggest lead yet.

Mining the earth for coal, erecting drilling rigs for oil and natural gas to pipe to our homes, smelting iron ore into buildings of iron and steel - all of these are fundamentals of the modern industrialised world, but they are nothing new.

Host Bobby Bognar crisscrosses the country to reveal what's behind a pancake breakfast. He gets fresh with a cow in a quest to learn if there really is butter in buttermilk pancakes.

UFOs are the biggest mystery of our time and somebody - or something - seems determined to keep it that way.

The confluence of two geological forces created and continues to build the island of Iceland. They also keep the geology active with global implications. For now the massive, but retreating, glaciers are keeping the glaciers in check.

For more than 500 years, Rome was the most powerful and advanced civilisation the world had ever known, built by an unprecedented mastery of engineering and labour.

All around the world are examples of physical evidence suggesting humans are not alone in the universe, but has this evidence been left behind for a purpose? Is it a series of clues we are meant to decipher? Giorgio A Tsoukalos investigates.

Ancient Top 10

From the riddles of the Sphinx to mummification and the pyramids, Egypt has seen some of the highest-profile archaeological finds in history. But with so many contenders, which secret has had the biggest impact on our view of Ancient Egypt?

After tracking Hitler's attempts to return to power through wealthy supporters in Argentina and Brazil, Bob Baer and Dr. John Cencich hit the ground in South America to tackle their biggest lead yet.

Mining the earth for coal, erecting drilling rigs for oil and natural gas to pipe to our homes, smelting iron ore into buildings of iron and steel - all of these are fundamentals of the modern industrialised world, but they are nothing new.

Host Bobby Bognar crisscrosses the country to reveal what's behind a pancake breakfast. He gets fresh with a cow in a quest to learn if there really is butter in buttermilk pancakes.

A swamp beast immortalised in the film "The Legend of Boggy Creek" is said to stalk the residents of a small town in Arkansas.

For Kevin Dykstra and his team, an 8-year quest to find a legendary boxcar at the bottom of Lake Michigan has now become a battle against nature itself.

From secret prisons to escape tunnels, ancient caves to mines, Bucharest in Romania is ripe with folklore. Discover the history of its secret underworld.

Former U.S. government insiders brought together by rock star Tom DeLonge team up to reveal what the government knows about UFOs.

Strange carvings suggest the Mayan city of Copan was ruled by the descendants of otherworldly beings. Are the astounding accomplishments of lost civilizations the products of ancient folklore or are they out of this world?

UFO Files

Delve into the aftermath and repercussions of the 1947 Roswell incident, when many believe an alien spacecraft crashed in New Mexico.

The Romans, with the greatest army in the world, are annihilated by Germanic tribes at the Battle of Teutoburg Forest. Go inside the culture of some of the most famous warriors to explore their weaponry, tactics and, ultimately, their psyche.