The area was proclaimed Bulgaria's first natural park in 1937. Scientists are still arguing over how the "stone forest" was formed. Some think that it was the result of a process similar to that by which cave stalactites are formed, others that it is a fossilised coral reef. The stones date back at least 50 million years, and cover about 653 acres.
The first drawings of the stone forest were made by the Englishman Thomas Spratt, a geologist and a sea captain, who visited during the Crimean War.
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