There are many ways to categorise and promote Bulgaria's heritage: traditional towns and villages, Thracian rock sanctuaries, nature, sun and fun on the seaside, and so on and so forth. But there is a number of places that defy being so easily pigeon-holed. Some of them were created by nature, others are manmade, their age ranging from the prehistory to the recent past. What unites them is that the first reaction they provoke in the viewer is "That looks weird. How did it come to be?".