Grenen is the northern tip of Denmark, a blade of sand beyond the town of Skagen in North Jutland where the Skagerrak and the Kattegat, two arms of the North Sea and the Baltic, meet at an angle and break against each other in a visible line of crossing waves, and it is walked to along the last two kilometres of the spit, with the sea closing in from both sides until only a strip of sand is left. The point is the end of a sandspit that the currents keep building northeast, a few metres a year, and the seam between the seas is not a wall of water but a front where two bodies of different salt, temperature and colour meet before they mix, seen as waves running in from the left and the right and slapping together on the last bar; standing with one foot in each sea is the custom, and bathing is forbidden, since the currents at the meeting pull hard. A tractor-drawn bus, the Sandormen, runs the two kilometres from the car park for those who do not walk, and the Grey Lighthouse near the base of the spit is climbed for the only view that makes sense of the shape, a thin curving blade of sand pointing out between two seas of different colour.
The point sits on one of the busiest shipping approaches in Europe, and tankers and freighters pass close to the tip between the North Sea and the Baltic, framed against the low bar. In April and May Grenen turns into the best raptor lookout in northern Europe: white-tailed and golden eagles, red kites, buzzards and cranes gather at the point, circling until the wind is right before striking out across the water toward Sweden, and birdwatchers line the dunes. Skagen itself drew the painters of the 1880s for its light, and the dunes have buried a church nearby up to its tower. Grenen is where two seas argue on a sandbar, and the country runs out under your feet.