Is this a joke? In a photographical sense yes, but not in its historical context.
In 1809 Holland was reigned by a French king: Napoleon Bonaparte, a brother of the great Napoleon. He was a good king with a keen interest in art and history. In this year he visited Drenthe and his curiosity was raised by Drenthe's Governor who told him about the mysterious monuments in Drenthe. They visited several hunebeds and according to the reports the king jumped on horseback on the the biggest and flattest capstone of D45. Now you can see what it must have looked like almost two centuries ago !

D45 is a big hunebed on top of a hill in the Emmer Dennen, the city forest near the center of the town. Imagine the original barrow that covered the hunebed on top of it and there you have a small mountain! D45 still has 6 capstones, but 2 are missing. Three of them are still on their 'feet' but three have tumbled down into the grave. The 17 sidestones and 2 endstones are complete and there still are 13 so called kerbstones around the burial chamber. There must have been 38 of them. The entrance to the grave on the south side is still there, but the capstone to this passage is missing.
D45 is a nice place to visit and an easy one to go to: a ten minutes walk from the station.