Watch: Inside the World's Longest Sea Caves | Expedition Raw

Geologist and National Geographic grantee Nicolas Barth was studying active faults on New Zealand’s South Island when he decided to climb down some cliffs and go for a swim. That's when he discovered the longest sea cave in the world. ➡ Subscribe: http://bit.ly/NatGeoSubscribe ➡ Watch all clips of Expedition Raw here: http://bit.ly/WatchmoreExpeditionRaw ➡ Get More Expedition Raw on Youtube: http://bit.ly/NGExpeditionRaw About Expedition Raw: Surprises, challenges, and amazing behind-the-scenes moments captured by National Geographic explorers in the field. Get More National Geographic: Official Site: http://bit.ly/NatGeoOfficialSite Facebook: http://bit.ly/FBNatGeo Twitter: http://bit.ly/NatGeoTwitter Instagram: http://bit.ly/NatGeoInsta About National Geographic: National Geographic is the world's premium destination for science, exploration, and adventure. Through their world-class scientists, photographers, journalists, and filmmakers, Nat Geo gets you closer to the stories that matter and past the edge of what's possible. PRODUCER/EDITOR: Nora Rappaport SERIES PRODUCERS: Chris Mattle and Jennifer Shoemaker GRAPHICS: Babak Shahbodaghloo and Chris Mattle VIDEO: Jeff Creamer and Nicolas Barth 3D CAVE MODEL: Aaron Curtis FEATURED IMAGE: Dave Bunnell Watch: Inside the World's Longest Sea Caves | Expedition Raw https://youtu.be/6CsIvI84TfA National Geographic https://www.youtube.com/natgeo