Ice cave

Ice cave under a residual snowdrift on Mount Twynam in late summer, its translucent ceiling sculpted by wind eddies and dust accumulating along ridge lines. Reddish stains in the snow are largely due to photosynthetic bacteria (Chlamydomonas nivalis), responsible for 'wine snow' with its deep red in high concentrations. Its photosynthetic constituent, chlorophyll, is masked by a sunscreen of carotenoid pigments. Kosciuszko National Park, New South Wales, Australia. (Photo by Auscape/Universal Images Group via Getty Images)