On the island of Funen in Denmark, the 700-year-old barrels found at an archaeological site in Odense has human excreta intact in "excellent condition".
What is more, the ancient faeces still smell bad!
The 14th century barrels, previously used to transport goods and store fish, were later used as lavatories.
Three barrels were stacked on top of one another to form a basic well.
They were tied together and lined with clay as well as having pipes at the bottom of them, said a report in the Copenhagen Post.
The archaeologists hope that the discovery would give scientists a better idea of what people ate in Denmark at that time.
It is not yet known whether the toilets were attached to a house or used as a public lavatory.
However, these toilets are not the oldest ones.
The earliest examples of toilets and sewers date to 2,800 BC are reported from outer walls of houses in parts of India and Pakistan, the report added.