The Alps’ magical ice caves risk vanishing in our warming world. For centuries, this spectacular underworld recorded the local climate and entranced visitors. Now its fairy-tale features are receding, drip by drip. Water percolating into freezing alpine caves like this one called Eiskogelhöhle, high in the Tennen Mountains south of Salzburg, Austria, sculpts itself into mesmerizing structures: huge Damoclean icicles, cones rising from below, and floor-covering cascades. They can be thousands of years old.
