Any ideas about what this European Space Agency photo is showing? It was taken 430 miles up by the French Pleiades satellite. (I admit that except for it's probably polar, Siberian, or something similar, I didn't get it.)

It is Antarctica, so no surprise there. But what's that dark streak? It's a supply caravan headed for the Concordia research station. The supplies are loaded on skis and pulled by a tractor. It's the best way of getting them there. The convoy is 1000 feet long and it takes ten days to get from the coastal outpost of Dumont d'Urville to the research station.