The Federsee (Feather Lake) in Southwest Germany.
It's a big lake that is completely surrounded by reed. It's a lot of reed, it's very dense and it is difficult to reach the lake. Therefore, long boardwalks were built that lead through the reed to the water. You can walk for quite a while right through the reed without even seeing the lake. Instead, you hear the lovely voices of many different birds who make their home there and raise their young.