Photos

Algiers on the Mediterranean coast.

A beach used by tourists west of Algiers.

A beach west of Algiers.

The modern city of Algiers lies near the Mediterranean coast, while the older city is on a steep hill crowned by the Casbah, or Citadel. This view is of a typical Casbah stairway.

An ornate doorway in the Algiers Casbah.

Algiers rooftop view.

Satellite dishes are ubiquitous in Algiers.

Algiers rooftop view of the Mediterranean.

The Issaouane Erg (sand sea) is located in eastern Algeria. Ergs are vast areas of moving sand with little to no vegetation cover. The most common landforms in the image are star dunes and barchan (or crescent) dunes. Star dunes are formed when sand is transported from variable wind directions, whereas barchan dunes form in a single dominant wind regime. Occasional precipitation fills basins formed by the dunes; as the water evaporates, salt deposits are left behind which appear as bluish-white areas. Image courtesy of NASA.

What look like pale yellow paint streaks slashing through a mosaic of mottled colors are ridges of wind-blown sand that make up Erg Iguidi, an area of ever-shifting sand dunes extending from Algeria into Mauritania. Erg Iguidi is one of several Saharan ergs, or sand seas, where individual dunes often surpass 500 m - nearly a third of a mile - in both width and height. The center and upper right of the enhanced satellite image is black sandstone rock. The light blue and white areas are chalky deposits and salt crusts left behind after water in the area evaporated. Image courtesy of USGS.

Sahara dunes at sunset.

Sahara dunes at sunset.