The chalk mines were used as shelters for the inhabitants and their property and then became underground hiding places, they are known as "muches" or hiding places in the Picard language.
The Underground City was dug by hand. At its peak, there were 28 galleries and 300 rooms. It was occupied from the Middle Ages until the 17th century, the underground passages fell into disuse until they were rediscovered by Abbott Danicourt in 1887.
There is ample parking, if you ask at reception it maybe possible to overnight stay.
