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 in northwestern Africa.
A handout image made available by NASA on September shows dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars, inferred to have been formed by contemporary flowing water (AFP Photo)
The Mississippi River Delta, where the largest river in the United States empties into the Gulf of Mexico. In this false-colour image, land vegetation appears pink, while the sediment in the surrounding waters are bright blue and green
Florida Park, by Joseph C. Claghorn, Born: Philadelphia, Pennsylvania 1869 Died: Bethesda, Maryland 1947 oil on canvas mounted on paperboard 15 x 11 in.) Smithsonian American Art Museum Gift of Mrs. Joseph C.