This is not actually part of the fence at Auschitz, it is the remains of an old barge. The picture does make me think of Auschwitz though.
For the curious out there I can tell you the metal parts you see in the picture were once the connections between the sides and deck of the barge. The thin vertical rods at the top ought to have been used to hold the deck planks in place. If this assumption of mine is true, they had deck planks thicker than 20cm (8 inches)!