In historical chronicles the famous Narzan was first mentioned at the beginning of the 18th century. It was Peter the Great impressed by the healing properties of Karlovy Vary waters who had started investigations in the region. The result was the discovery of "Acid Spring" and already at the end of 18th century the first descriptions of therapeutic properties of famous Narzan were published as well as the highly mineralized Tambukan mud which have bactericidal and regenerating effects.