The town of Pernik, about 20 kilometres west of Sofia, hosts the annual Surva masquerade festival. This year's event, which brought together more than 6,000 participants from Bulgaria and abroad, was included in National Geographic's list of the Best Winter Trips 2014.
The games are deeply rooted in Bulgaria's pagan traditions. For centuries people have been putting on scary costumes and visiting the houses of fellow villagers on the evening of January 13th to banish evil spirits and bring a message of health, fertility and well-being.
Men wear heavy bells around their waists while dancing around. It is believed that the sounds scare evil away. Masked men, women and children performing ritual dances to drive away evil spirit are called kukeri.
Many of the masks and dummies participants carry are made from the skins of cattle -- a material that was traditionally used for clothing in the past.
Some kukeri carry a thick wooden rod as a weapon to fight back evil.
The ritual mask is believed to give superhuman powers to the person wearing it. According to traditional beliefs it provides protection from the demons. Some kukeri put soot on their faces as an alternative to covering it up with a mask.
A group brought a donkey, spurring huge interest among the audience, especially its youngest members. Although donkeys once were a common sight in Bulgarian villages and were faithful helpers to the men working in the fields, it is rare to see them in modern municipalities today.
The kukeri perform their choreographed dances in the town square before hundreds of viewers.
Every move has a magical meaning. The swinging of the kukeri is a symbol of the swinging of wheat in the field. The dancers are often pushed down to the ground, which is believed to bring fertility.
Women wearing traditional Bulgarian clothes perform folk dances. The oldest female member of the family offers homemade bread to the kukeri, which is a sign of gratitude for driving evil away from her home.
All happens under the sounds of traditional Bulgarian music.
The festival is eagerly awaited by local business. Small kiosks around the main spot of the event offer traditional grilled meat meals, salads, and plenty of wine to warm up.
People of all ages take part in the masquerade. This year's oldest participant was 86. Velin Georgiev, 57, from the village of Kalchovo in Yambol, told SETimes he has been enchanted by the masquerade tradition for 40 years and is passing it on to his children and grandchildren.
This year's youngest participant was 5. About 1,200 children younger than 14 took part in this year's games. Snezha Ivanova, a teenage girl from the village of Chelnik near Yambol, said she has participated in the masquerades since she was a young child.
In 2012 the festival was included in Bulgaria's National Representative List of the Intangible Cultural Heritage as a Living Human Treasure. It is one of the forerunners among the Bulgarian candidatures for inclusion in UNESCO's World Heritage List.