** Beware of the last photograph.
The grass snake (Natrix natrix), sometimes called the ringed snake or water snake, is a Eurasian semi-aquatic non-venomous colubrid snake. It is often found near water and feeds almost exclusively on amphibians.
The first three photographs belongs to the same snake. It is a very shy creature and will run for the water as soon as sees you. Particularly hard to photograph. In this special case, I saw it a bit far from water, in open area where I am faster. After a minute or so of hide and seek, she decided to turn and face me straight! Amazing moment.
More on Wikipedia.