High Quality Content by WIKIPEDIA articles! The Grand Canyon Caverns (Havasupai: Tathiil Nwa?a or Tathiil Nha?a,35°31?44?N 113°13?54?W? / ?35.52889°N 113.23167°W? / 35.52889; -113.23167Coordinates: 35°31?44?N 113°13?54?W? / ?35.52889°N 113.23167°W? / 35.52889; -113.23167), located just a few miles east of Peach Springs, Arizona, lie 230 feet (70 m) below ground level. They are among the largest of dry caverns in the United States. Dry caverns are a rarity in that as little as 3% of caverns in the world are dry. Because of this fact, stalagmites and stalactites are very few in numbers. Air comes into the caverns from the Grand Canyon through 60 miles (97 km) of limestone caves. Scientists were curious as to how far the caverns extended and looked for a safe means of finding out. Rather than explore the canyons, which could take years, red smoke flares were ignited by University of Arizona students, and two weeks later red smoke was seen protruding from vents, near Supai, AZ, in the...