From mid-May to mid-June, more than 6000 specimens of the rare orchid Cypripedium calceolus, the bright yellow lady's slipper, bloom in the nature park municipality of Elmen in the hamlet of Martinau. The particularly high occurrence of a type of fungus needed for the germination of the flower enables the mass development of the plants.

The highly sensitive lady's slipper, also known as "Kriemhild's helmet", is a protected species and is one of the most magnificent wild orchid species in Europe. The lady's slipper was named Orchid of the Year in 2010.

Mountain guards watch over the 2 ½ hectare area and make sure that no one leaves the paths or even digs up plants.