france western pyrenees pyrenees national park pyrenean landscape scenery overview highlight sight gentau lake mountain lake rock basin ice-eroded hollow cirque lake tarn post glacial lake distinctive shape ayous lakes refuge summer pastures grassy pastoral plateau hiking footpaths mass of fallen rocks open air lac gentau lac de montagne ombilic glaciaire lacs d'ayous refuge paysage pyrénéen point de vue plateau herbeux pastoral chemins de randonnée pleine nature - Alamy