There are 7,000 concrete bunkers and fortifications on the beaches along the west coast of the Jutland Peninsula, an ugly reminder of the German occupation during World War II.
In the 1990s, Denmark commissioned 24 international artists to commemorate the 50th anniversary of the war and the liberation of Denmark.
British sculptor Bill Woodrow transformed four of the decaying bunkers into mules by attaching steel mule heads and tails onto the existing structures. As mules are infertile, the artist used them to symbolically say that the terrors of war should not be able to reproduce. They were installed in 1995.