A journey to some of the mysteries of how the early Celts emerged and expanded since the 8th Century BC: from the collapse of the Hallstatt salt mines, to the bizarre rituals inside Bull Rock cave, the location of the lost city of Pyrene or the strange constructions found in Glauberg or Alteburg.

In the 2nd Century BC, Celtic tribes established prosperous cities dedicated to trade along the Amber Road and the Danube. But external threats to their society forced them into smaller fortified settlements known as oppida. This marked the beginning of the decline of the Celts in Central Europe.