Of all the troglobites, it is perhaps the olm that is the star. Troglobites are built to survive in the dark cave systems below the earth's surface.

Population by population, species by species, amphibians are vanishing off the face of the Earth. Watch the full episode now.

Scientists are struggling to understand why frogs are dying all over the world. But everyone can be a part of the solution. Here are some ways you can help.

Learn more about some of the frogs featured in Frogs: The Thin Green Line on this interactive map.

Scientist Tyrone Hayes is studying the how agricultural chemicals, including fertilizers and pesticides, are affecting the health of frogs.

Allison Argo, the filmmaker behind Frogs: The Thin Green Line, discusses the making of the film in this Web-exlusive video.

(Airs Sunday, April 18) More than a third of all amphibians have already been lost, and more are disappearing every day. A fungus called chytrid has been identified as the major culprit.

Frogs filmmaker Allison Argo talks about her recent screening in London, and how you can make your own backyard frog pond.

Go behind the scenes with me, Allison Argo, as I share stories from the making of Frogs: The Thin Green Line.

Amphibians are linchpins in their ecosystems and important in medical research. What would the world be like without them?