Kukeri is a pagan tradition spotted in many countries in Europe under different names, in which men dress in outfits often made of animal fur, with big copper bells attached on their belts and with faces hidden behind frightful masks. Their purpose is to scare evil spirits away and they do so by dancing, waving the fur on their costumes and shaking the bells on their belts. See some Kukeri here
In Bulgarian folk tales there is a common saying to depict a hero travelling a long distance - "Through nine mountains and over to the tenth". The pattern that you see on the mountains is based on traditional embroidery. This one in particular is called "Elbetitsa" and means "Harmony in the world". I have hidden many different embroidery patterns in my illustrations linking them to this old tradition of protecting oneself from harm.