Trou Madame, Lot, France

From the large entrance there is a wide stooping height passage with a sandy floor which, after 50 metres, leads to a 1 metre drop down to a lake. Kitting up is done here. Depending on water levels you may have to crawl for 10 to 20 metres until the water becomes deep enough to swim and the lake can be up to 50 metres long before the passage sumps. Sump One is typically 5 metres high by 10 metres wide with very clear water. All the passages tend to meander with few straight sections. In places large banks of clay are passed.

Would you like to see more? Go to the page HMS Britannic Expedition.