The Ark of the Covenant, a golden chest built to hold the Ten Commandments, is one of the most important religious artifacts in the world. Jews, Christians, and Muslims believe that it was the presence of God on earth. But over 2500 years ago, the Ark disappeared. Ever since, legends, theories and Hollywood blockbusters have tried to explain what happened to it. Was it destroyed or captured? Or could it still exist? Olly explores the plausibility of one of the most exciting theories: that the famous Ark of the Covenant was smuggled out of Jerusalem, through the deserts of Egypt, into Ethiopia and that the Ethiopian Orthodox Christian Church - a sect of Christianity millions strong - believes they protect that very same Ark to this day.

Carved into the Peruvian desert thousands of years ago, the Nazca Lines have puzzled archaeologists and laypeople alike ever since their discovery 100 years ago. Olly travels to ancient cemeteries and Nazcan cities that are curiously off-limits to camera crews. He explores underground tunnels used in psychedelic cult initiations and tries to venture into the spirit world himself to unravel the mystery of the Nazca Lines.

El Dorado -- its very name has become synonymous with legend of a mythical city of gold lost in the wilds of South America. But is it really a myth? Is there actually a city packed with gold hidden somewhere in the Andes? For hundreds of years explorers have mounted expeditions to find it. Now Olly has learned of new clues that could mean one of the greatest archaeological discoveries of all time is right around the corner. From the golden churches of the Incan capital Cusco, Olly follows the trail of El Dorado along a road of ruins deep into the remote Andes Mountains, leading an expedition that promises to open a new chapter in the centuries-old hunt for the City of Gold and change the face of archaeology.

Perhaps the most famous lost city of the ancient world, Atlantis is an enduring symbol of mystery and beauty. Beginning with Plato, people have dedicated their lives to finding the missing continent. But what happened to Atlantis? Are there forces of nature deadly enough to annihilate an entire civilization in an instant? To find out, Olly explores the depths of the Mediterranean Sea, travels to an ancient city swallowed by the earth, treks Europe's most active volcano, and journeys to the site of one of the world's worst disasters. Through dogged reporting, Olly reveals new evidence that could explain the mystery of what really happened to the fabled city of Atlantis.

The infamous Amber Room is the most valuable piece of missing art in the world. For more than 200 years these lavish wall panels, made entirely from carved amber, gems and gold, were the pride of the Russian czars - that is, before the Nazis looted the treasure in 1941. It was taken to a medieval fortress in the city of Koenigsberg, which was the last place it was ever seen. Olly takes up this great unsolved mystery of WWII, beginning in the modern hell hole of Kaliningrad. He then travels through Nazi hideouts across Europe to piece together clues that narrow down the final hiding place of this treasure. From an underground German fortress, into secret Czech mine-shafts, and by drilling deep beneath a medieval castle used by the SS, Olly uncovers exciting new evidence that could lead once and for all to the discovery of the Amber Room.

Olly discovers some lost, ancient mummies from different cultures that were recently re-found in a German museum and unravels how they were used by Hitler's Secret Service for the Nazi's ultimate propaganda mission.

Long before Alcatraz, there was Devil's Island - the most notorious and vicious prison complex ever constructed. Escape was said to be impossible. But was it? Olly explores the horrors of prison life and tests first-hand whether tales of great escapes could be true.

Olly Steeds heads to England's Sherwood Forest to explore the legends about Robin Hood by reliving them as an outlaw in Plantagenet England.