The last time the Lesse appears before it emerges in the open air at the "Han Hole".
After a trip of 250 metres, the visit reaches its climax with the gradual arrival of the daylight.
At the end of the visit, it is traditional to fire a canon.
In the old days, the canon was fired to listen to the echoes of the caves - and especially to chase away any evil spirits.
The reappearance of the river under this majestic vault has fascinated man since the end of the Neolithic age. This was a place for pilgrimages and people came from all over Europe. The many items, often precious, thrown into the water bear witness to the cult worshipping the river and the divinities in he caves. Hundreds of the items found here are on display in the "PrehistoHan" in the centre of the village.