Photo by Robbie Shone @shonephoto Just south of Salzburg and tucked within the Alps, Eisriesenwelt is the world's biggest ice cave. A tour with veteran guide Siegi Kaml (pictured) ends with visitors arriving at a frozen lake inside a chamber known as the Eispalast, or “ice palace.” But as temperatures rise, the volume of ice in many caves is shrinking. And in some, the ice is no longer perennial: It's melted by rain and warm air that infiltrate the caves. In the article "When the Magic Melts," in the October issue, I document the contributions of scientists—and tour guides—as they work against the clock in this rapidly disappearing landscape.