Grenen

It's a very special natural phenomenon when the two seas, Kattegat and Skagerrak, meet at the top of Denmark.

There are great forces of nature at play here, and in fact, the sea wall that makes up Grenen has grown by 1 kilometre in length over the last 100 years. It's in constant motion, and many people think that Grenen points north, but in reality it points east. This also tells us something about the wind and the forces of the sea.

As fascinating as it is, it's just as dangerous if you get too close. That's why bathing at Grenen is strictly forbidden.