The Nettlebed Cave was thought to be the deepest cave system in the southern hemisphere until explorers found the nearby Ellis Basin cave system to be deeper, making it the deepest known cave in New Zealand. It has been explored to a depth of 3.360 feet (1,024 meters). Its 20.75 miles (33.4 kilometers) of cave passages make it New Zealand's second longest.
The six-member cave explorer team returned to the Pearse River cave system for the third time in the last three years, pushing the limits a bit further each year. During the 17-hour record breaking dive, Challen was able to break his own depth record set at 636.5 feet (194 meters) in 2010. He and his team of support divers used a total of four underwater habitats for decompression.
Natural underground spaces called caves are found throughout the world, but only a portion of them have been explored and documented by cavers. With 390 miles (628 kilometers) of surveyed passage, the Mammoth Cave in Kentucky is currently the longest known cave system. The picture shows the entrance to the Little River cave system in Florida.
Source: Global Adventures