Wildlife Photography by Carsten Peter

HANG SON DOONG, or “mountain river cave,” is 2.5 miles long with a max width of 300ft and a max height of 600ft, making it the largest cave passage in the world. Exploration of Hang Son Doong and the surrounding system began in 2009, and a year later National Geographic writer Mark Jenkins and photographer Carsten Peter accompanied the mapping team on its second visit.