Cirkular, marked route, starting and ending usually in the largest town "Tønder" its a flat route, with some difficult footing - in the marsh areas of southern Denmark

https://udinaturen.dk/shelter/9883

https://toendermarsken.dk/marskstien/kort/

36 km long route in Denmark, Starting in Vejle, at the end of "vestbane vej" and ending in Billund by Lalandia, at "firhøjvej" - its an officially marked route 

https://www.vejle.dk/borger/vaer-aktiv/aktiv-i-naturen/find-ruter-i-nat… 

https://www.vejle.dk/media/17081/bindeballestien-folder_web.pdf