the st. beatus caves – a natural wonder by lake thun (st. beatus-hohlen – das naturwunder am thunersee)

beatus caves natural wonder lake thun beatus-höhlen das naturwunder thunersee oder beatus-hoehlen beatus-hohlen interlaken canton bern switzerland schweiz adventure ancient art attraction background black cave cavern caving clip dark darkness deep design drawing earth entrance formation geology glowing graphic green ground hole landscape light limestone mountain nature night outdoor outside rock scene scenery stalactite stalactites stalagmite stalagmites stone tourism tourist travel tunnel underground water yellow