Wet sandy beach, cloud reflections, Isle of Rum, Scotland

The sound of sand

If we had video instead of a still shot, this impossibly broad buffed-marble countertop would reveal itself as swirling silt and silica. Walk the flats on a drier day and you'll not only see but hear the sand, reputed to 'sing' with each of your footsteps. The beach here at Laig Bay, on the Scottish island of Eigg, is one of several around the world that feature singing sand, which produces a sort of breathy whistle when compressed. Science hasn't fully explained the phenomenon—it could be caused by friction between silica particles, the air separating them, or some mix of both. In any case, as you tread along this quiet coast at Britain's edge, don't be surprised if nature hums a tune along with you.