This all happened one evening, when I was in Krakow, Poland. With few friends we went to the lake situated close to the center of the city. One of us was there some years ago. We had first searched on a map, than with car between streets and at the end we found it. Once we have got out of the car it was already pass the twilight and sun was behind the horizon.
Reaching the edge of the lake, each of us was surprised. Lake was huge. Certainly you do not expect such a size in the city. Very steep edges falling down more than twenty meters. You certainly do not want to fall down. So we stayed at the edge and kept looking on it.