article_snippet: Ryan, originally from America but now living in Beijing, China, described Vietnam's Hang Son Doong cave as like an extraterrestrial planet.
article_snippet: He said: 'This was my third visit to Son Doong.
article_snippet: The process took Ryan eight days to complete and Ryan was required to take a lot of ropes, harnesses and safety equipment into Vietnam's Hang Son Doong cave with Ryan.
article_snippet: Ryan explained that while Ryan was within Vietnam's Hang Son
article_snippet: Doong cave Ryan wouldn't have been surprised to have seen a dinosaur.
article_snippet: Ryan said: 'Being inside Son Doong is absolutely unreal.