Icebergs and an Adelie penguin, Adelie Land, Antarctica . Antarctica, the sixth continent, is a unique observation point for atmospheric and climatic phenomena; its ancient ice, which trapped air when it was formed, contains evidence of the Earth's climate as it has changed and developed over the past millions of years.

American cemetery north of Verdun, Meuse, France . Covering some 40 hectares (100 acres) at Romagne-sous-Montfaucon, 40 kilometers (25 miles) from Verdun , the American cemetery was dedicated in 1935 by the American Battle Monuments Commission. The commission was created in 1923 at the request of General Pershing, who had taken part in the American offensive of 1918. Its aim was to undertake architectural and landscape studies in order to restructure American cemeteries and commemorative monuments in Europe . Whereas the French army chose to build permanent cemeteries where temporary cemeteries had been made during the hostilities, the American army opted to create a single cemetery. Some 25,000 American tombs scattered around Verdun were then brought together at Romagne where, after almost half the bodies were repatriated to American soil, 14,246 soldiers have lain ever since.

Worker resting on bales of cotton, Thonakaha, Korhogo , Ivory Coast . Cotton crops occupy approximately 335,000 square klilometers worldwide, and use nearly one quarter of all pesticides sold.

Elephants in the Okavango Delta , Botswana . The Okavango Delta is the world's largest inland delta, flooding seasonally, and is populated by five ethnic groups of people, sharing it with hundreds of species of animals.

Icebreaker Louis Saint Laurent in Resolute Bay, Nunavut Territory , Canada.

Islet in the Sulu Archipelago , Philippines . More than 6,000 of the 7,100 Philippine Islands are uninhabited, like this islet in the Sulu Archipelago, a set of 500 islands that separate the Celebes and the Sulu seas. Their extraordinary biodiversity is under threat, not from distant industrial sites but from the effects of global pollution. These islands, which barely rise above the surface of the water, are among the first potential victims of global warming and are certain to disappear when the sea level rises.

Road interrupted by a sand dune, Nile Valley, Egypt . Dunes cover nearly one-third of the Sahara , and the highest, in linear form, can attain a height of almost 1,000 feet (300 m). Barchans are mobile, crescent-shaped dunes that move in the direction of the prevailing wind at rates as high as 33 feet (10 m) per year, sometimes even covering infrastructures such as this road in the Nile Valley.