A photo exhibition to mark the 96th anniversary of the beginning of organised speleology in Bulgaria will be opened today on the Lovers' Bridge near the National Palace of Culture (NDK). This was announced by the organisers of the "Pod Raba" (Under the Edge) speleological club. The exhibition includes 60 photographs that reveal some of the most interesting and beautiful secrets of the underground kingdom. 

The exploration and research of caves in our country dates back to the end of the 19th century and is associated with the Škorpil brothers. Their work was later continued by Dr Ivan Buresh, and on 18 March 1929 the first Bulgarian Speleological Society was founded. 

Since 1975, Bulgarian speleologists have been completing the Main Card Catalogue of Bulgarian Caves, which contains data and maps of more than 6,000 explored caves. The caves still hide "white spots on the planet" where man has not yet set foot," the organisers say.