Château de Montségur
The ruins of Montségur are perched at a precarious 1,200 metres (3,900 ft) altitude in the south of France near the Pyrenees Mountains
Montségur was supposedly one of the last hold-outs of the Cathars from the Catholic Church, it eventually fell and became of interest to Otto Rahn. Rahn had believed them to worship Lucifer and that the Grail (believed to be part of Lucifer’s crown) would be found in the midst of some underground holding.
Part of the Cathar spiritual journey was the Endura, in which one would go into the mountains for 2 moons and live on nothing but bread and water, but unlike the fasting the Initiate would end up dead once a certain state of spirituality was reached.
"Their doctrine allowed suicide, but demanded that one did not end one’s life because one was weary or it or because of fear or pain, but because one had attained a perfect state of dissolution of matter. This kind of Endura was allowed when it took place during a moment of mystical insight, of divine beauty and kindness. …It is only one step from fasting to suicide. To fast requires courage, but the final act of the mortification of the flesh requires heroism. The consequences is not as cruel as it may seem."(Rahn, Crusade against the Grail)