At Denmark's nothern tip, you can literally stand with each foot in a different sea. The North Sea meets the Baltic Sea here—the water can be calm on one side and quite choppy on the other. Many a ship found its end here where the two seas clash, so don't go swimming in these dangerous waters. To get to the tip, take a tractor trailer called "the Sandworm" from the nearby parking lot, or walk for about a mile along the beach.
Grenen, unknown, 9990, Denmark