Grønsalen
Vordingborg Municipality, Denmark
Grønsalen or Grønjægers Høj is located near Fanefjord Church on the Danish island of Møn. Some 100 metres long and 10 metres wide, it is Denmark's largest long barrow and is widely recognised as one of Europe's outstanding ancient monuments.
Monument data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).