The visit

• In summary
  

  
  The Neptune's caves, one of the most underground caves of Belgium dug by the "Eau Noire" river (Black Water River) more than 1 million years ago.
  
  The guided tour begins with a natural setting of stunning beauty, at the foot of a Givetian (a period of timve over 300 million years ago) limestone cliff, on a catwalk overlooking the river Eau Noire. (see the plan of caves)
  Afterwards, you are taken along two upper galleries which allow you to view fabulous scenery including beautiful rock formations.
  It will not be unusual to see impressive varieties of bats such as the rhinolophe or the large murine during your tour.
  After the rock formations you'll continue the adventure on a small boat, along the meanders of the river where you will enjoy a music and light show unique to Europe.
  To finish the tour, there is a romantic exit accompanied by musical extracts of Vangelis and stroboscopic effects that will not fail to fill you with wonder.
  
     
  
  

• Hydrogeology
  

  
  The Neptune's caves, it's also one of the most important hydro geological phenomena of Walllonia !
  
  Discovered at the end of the 19th century, the Neptune's caves are still called "the Adugeoir's caves" because of the disappearance of the river at that place.
  The river flows into the cave through different cracks caused by erosion and disappears into a siphon that nobody has succeeded in crossing to this day.
  These xater appear 40 to 48 hours later in the resurgence of the Avignon Bridge in Nismes, having gone through an underground tunnel of almost 3 miles.