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.