Roman oil jug
If you come across an ancient-looking jug, don’t be tempted to crack it open. There’s nothing inside that could be worth more than the potential value of the jug. The OP found this in the Netherlands in an ordinary garden and thought it resembled jugs from an ancient civilization.
The OP was spot-on with their guess. Someone on Reddit said that the jug looked to be Roman and quite possibly made of terracotta. The Romans were really into pottery, as evidence has shown. It’s remarkable that this jug is fully intact. They could pawn it for some serious cash.