Millions of years in the making, underground caves sustain delicate ecosystems that are rich in biodiversity. In this film, explorers of the vast cave networks in the southern United States explain the importance of preserving these subterranean worlds.The Short Film Showcase spotlights exceptional short videos created by filmmakers from around the web and selected by National Geographic editors. The filmmakers created the content presented, and the opinions expressed are their own, not those of National Geographic Partners.

Source: Explore the Hidden and Fragile World Inside Caves