Disc 8 includes bonus photos and chapter notes with bibliographical references in PDF format.
System Details
System requirements for bonus content: Computer with CD drive, Adobe Acrobat Reader.
Summary
Chronicles attempts by scientist-explorers to locate the deepest cave on Earth, focusing particularly on the 2004 efforts of American Bill Stone in the vast Cheve Cave of southern Mexico and Ukrainian Alexander Klimchouk in the supercave Krubera in the Republic of Georgia.