The International Festival of Masquerade Games,also known as Surva, is an annual event where dancers called Kukeri adorn colorful masks, or traditional dress,and scary costumes. The event has its roots in traditions practiced by the Thracians who once inhabited the area.
Meant to drive out evil spirits and encourage a splendid harvest, the fearsome Kukeri dancers can actually be seen in villages across Bulgaria. However, and to witness the largest of example these dancers,Pernik is the place to depart.
Source: atlasobscura.com