Jewel Cave, USA

In the United States is a well-known cave, to whose honor the popular flash game - Jewel Cave was called. Although the cave was discovered more than a century ago, the great research started relatively recently. So far, about 257 km of the underground vaults have been investigated. The depth of the longest excavated mine forms 193 meters. The unique cave of impressive size has only one natural entrance, which is located in the northwestern part of the labyrinth.

When the cave began to attract the tourists, it was decided to create an additional entrance. The tourists visit Jewel Cave to see the huge halls, whose walls are covered with the incredibly beautiful calcite crystals. The thickness of some crystals is 17 cm. Thanks to the illumination, some of the rooms in the cave are simply magical.

The second longest cave in the world is excellent for visitors. A part of their passages and galleries are equipped with the comfortable little bridges. The distinctive feature of the cave is the strong wind. In some branches it can reach the speed of 15 m / s. Thanks to the wind, the cave was discovered by the researchers Alber and Franc Michaud in 1900. They noticed the whistling wind from a small opening in the ravine. Jewel Cave is actively researched throughout the year, so the overall length of its complicated passages and galleries is literally increasing every day. Next - Son Doong