Pobiti Kamani is a rock formation located in Varna Province, Bulgaria. There are a number of theories regarding its origin, with two broad hypotheses. According to one, the formations are the result of coral activity, while another explains the phenomenon with the prismatic weathering and desertification of the rocks, the formation of sand and limestone concretions, or lower Eocene bubbling reefs. The stone pillars were first described by the Russian archaeologist and historian Victor Teplyakov in 1829, and the site was designated a natural landmark in the late 1930s. This photograph shows the pillars of Pobiti Kamani in 2016.Photograph credit: Diego Delso