The show ended up moving through two seasons without a discovery from the Lagina brothers. During the third season, that all changed. While they drained a hole, they found artifacts like a ceremonial Roman sword. This suggested that the Romans were in North America before Christopher Columbus.
At the end of season three, they had unearthed many artifacts, leading them to feel that they were on the best track. As season four started, they wanted to identify one of the interesting items they found – a handmade copy of a French map.