Déroc waterfall towers 30m above the small glacial valley of the Gambaïse stream. It has impressive views of the Marchastel region with the large stretches of Aubrac granite in the background. You can reach the waterfall from Nasbinals via a little lane. Walk along the stream and you will reach the edge of the ravine where the Bès River and Salhiens Lake meet and flow to the basalt edge beneath which a cave has formed. Doctor Prunière discovered the cave and used it to hide from highwaymen. Its ceiling is covered in enormous basalt prisms whose geometry is incredible to see.