A lake on the Nera Keys where the water is blue as a lagoon. This lake is located at the entrance of a cave on a 8 km trail through the forest and on the edge of the Nera River where the trail is made through the walls of the mountain with portions where you must hold on to the steel cables to not fall into the water. It's a very beautiful place in Romania, but it has to be explored carefully because it is a land full of vipers.