take metro in Prague to Jinonice or Nove Butovice. there are fishponds in the area.
Dragonflies emerge in early morning. It takes long time for them to develop and open wings. Four-spotted dragonfly does not immediately fly. It needs to hide in low shrubs and dry wings. After about 24 hours it is able to fly--then it doesn't like to be photographed. If it is chilly, it takes longer for the dragonfly to mature.
The dragonflies usually merge in early morning, but it takes a long time for them to evolve and dry their wings. The best time to photograph Four-spotted Chaser, Libellula quadrimaculata.