C. and A.D. 500 by brushing away the dark top layer of barren desert to reveal the light, sandy soil underneath, wrote Clive Ruggles, an archaeologist from the University of Leicester in the United Kingdom, in an email.

MSN: Peru's mysterious Nazca Lines form a labyrinth, says study

But further measurements using a laser and looking for reflections showed that much of the ice is covered with a layer of dark material tens of centimetres thick.

BBC: Mercury's water ice at north pole finally proven

The blue layer of sky had given way now and was turning dark like the rest.

NEWYORKER: Beginners