Their aim was to research the allegedly deepest locality of Galtaj Soogtej aguj, which has not been explored up to now. It is situated in Chentij ajmak in the island of proterozoic limestones. According to a geological map they spread at the area of about 50 km² and border the territory of the Commonwealth of Russia. The cave represents a senile phreaticaly formed vertical passage with depth of 45 m. Its bottom is a siphon created by organic material floated from surface into underground. I do not assume easy passing the next spaces. We gathered information about the cave from our Mongolian friends who registered dropping the rope into underground to find out an unknown cave depth when television shot this event. Next aim was to research caves in surroundings of Lake Chubsugul in the north of Mongolia in ajmak of the same name (Chubsugul). Here karst is located at the area of 16,500 km² in carbonate rocks from the Proterozoic and Cambrian Periods. Their thickness is over 1,000 m. This is the largest karst area in Mongolia. There is preferred shaman religion. According to legends in the unreachable dry caves cult objects are hidden separately from mummified shamans. According to Mongolian old superstitions these caves are consecrated and their desecration courts revenge of dead shamans. At this area we have staid for 9 days but we have found no caves there. Surface of limestone area is weathered to a great extent and it covers possible entrances into underground. We only registered clints, ponors, and the Char-us spring with water capacity of about 3 m/sec. In this area we just expect existence of a more extensive cave system. We also visited Dornogov ajmak. Chamaryn chid monastery is situated about 34 km south of Sajnsand. Approximately 2 km from it B. Batar gesguj lama showed us smaller lava caves where in the 19th century D. Danzanrabz, a well-known Mongolian monk and intellectual meditated for 104 days with minimal food. On the way back in the Aja Gulf in Bajkal we visited the Aja-Rjadovaja Cave System, which is the most extensive cave of the area with the length of 1,350 m (denivelation of 64 m). We also visited the Vologodskogo Cave (deepth of 20 m) and the Oktjabrskaja Cave (deepth of 33 m) with an archaeological find from 5-10 000 years B. C. to late the Middle Ages. These caves are very old. It is documented by 20 millions years old fish bones in the caves sediments.