18th Nationalpark Bike-Mararthon - all around the Swiss national park The 18th Nationalpark Bike-Marathon takes place on Saturday, August 31, 2019 and runs once around the impressive landscape of the Swiss National park. The children compete at the Kids Race and Kids Parcours on the finishing area in Gurlaina on Friday, August 30. Come and join the thrilling race atmosphere at probably the most beautiful marathon course in Europe - including rolling starts for a smooth beginning and a sustainability concept.