Katmandu.  (photography: AP)

A Nepalese girl looks for snails, used for medicinal purpose, in a paddy field on the outskirts of Katmandu, Nepal,

Jemen.  (photography: AP)

Sana'a, Yemen: Young soldiers stand guard as protesters demonstrate, demanding that the relatives of former president Ali Abdullah Saleh be fired from army and police postsPhotograph: Hani Mohammed/AP

London.  (photography: Reuters)

London 2012 Opening Ceremony - The Olympic rings are seen during a pyrotechnics display at the pre-show before the opening ceremony of the London 2012 Olympic Games at the Olympic Stadium July REUTERS/Suzanne Plunkett

London.  (photography: dpa)

London. (photography: dpa)

London.  (photography: Getty Images)

Christina Loukas competes in the women's Springboard Diving semi-final Christina Loukas of the United States competes in the women's Springboard Diving semi-final on Day 8 of the London 2012 Olympic Games.

Moskau.  (photography: AFP)

Moskau. (photography: AFP)

Shanghai.  (photography: Reuters)

Lightning pierces dark sky over Shanghai (Photo: Aly Song / Reuters)

Jakarta.  (photography: dpa)

Indonesian men compete in a palm tree climbing race to mark the anniversary of Indonesia's independence day in Jakarta. See this only in Indonesia

Kanada.  (photography: AFP)

Kanada. (photography: AFP)

Kabul.  (photography: Reuters)

A man sleeps near a make-shift carousel as he waits for customers in Kabul August REUTERS-Omar Sobhani

New Orleans.  (photography: AFP)

Image detail for -NEW ORLEANS — Slowing-moving Tropical Storm Isaac closed in on the U. Gulf Coast on Tuesday and was expected to make landfall as a full-blown hurricane in the New .

Mars.  (photography: AFP)

Layers at the Base of Mount Sharp. A chapter of the layered geological history of Mars is laid bare in this postcard from NASA's Curiosity rover. The image shows the base of Mount Sharp, the rover's eventual science destination.