PIERRE-SAINT-MARTIN - A famous abyss near Sainte-Engrāce, first explored from 1908 by Edouard Martel, then (in 1934 and 1952) by the team of Dr. Cosyns, who spent a long time in Soule. It is said to be 1,358 m deep, and one of its caverns (the "Verna" hall, 728 m below ground level) is supposed to be the largest underground cavern in the world. A tunnel known as the "EDF [Electricity Board] gallery" was dug out under the Arpidia canyon in order to reach it, but as this access is tricky to follow it is strictly controlled. If a search engine selected this single page separated from the remainder of the Real Estate Web Gaztelua ... click on