kallektuffquell waterfall on mullerthal trail, spring with crystalline calcareous water

background bank calcareous cascade cascading color concept course crystalline ecosystem environment erosion europe fall falling forest formations fresh geology green hiking idyllic kallektuffquell lake landscape limestone luxembourg luxemburg moss mosscovered motion mountain mullerthal natural nature nobody outdoor park pond reflection reserve river rock route rural sandstone scenic season source spring stone stream tourism trail tranquil travel trees tuff wall water watercourse waterfall wilderness woods