In 2009 a team of British Cavers discovered a cave deep within the jungle of central Vietnam. After exploring the cave passage for six kilometres, their way was barred by a formidable and gigantic rock face they named ‘The Great Wall of Vietnam. This year they have returned with the right climbing equipment and a team of scientists set on discovering if this is the World’s Biggest Cave, and what secrets it may hold? Subscribe to Our World: https://bit.ly/3xnPuGL This film was first broadcast: 2010 Watch More Documentaries Our Life - https://bit.ly/3A8xRMJ Our History - https://bit.ly/3rUpdhL Our World - https://bit.ly/3ftuckM Our Stories - https://bit.ly/3ynfFyk Our Taste - bit.ly/3OZoDcV Explore Our World and watch some of the most successful nature documentary series about the environment and the wonders and dangers nature has to offer. We will be posting some of the longest-running and most successful nature documentary series, revealing the trials and tribulations of life on Earth and often for the first time, the secrets of the natural world in all its wonder. Content distributed by ITV Studios.