This geological phenomenon manifesting itself in the pleasant landscape of the Buzau hills is one of the great curiosities of the Carpathians. The craters of small volcanoes reveal a thick, muddy, grey clay. From time to time they erupt, releasing huge bubbles! Some people come here to coat their bodies in the mud, as much for Instagram as for its reputed virtues. These formations can be seen on four plateaux at two sites which are 3km apart.