People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

Katjinga, a Rhodesian ridgeback dog who lives on a 20-acre farm in Germany, adopted an abandoned pot-bellied piglet in August 2009. The tiny black piglet, named Paulinchen, had been so small at birth that her mother likely overlooked it. Katjinga's owner, Roland Adam, found the piglet alone and cold and brought it to his 8-year-old dog. (Photo by Fame Pictures)

“The Lockheed SR-71 “Blackbird” was an advanced, long-range, Mach 3+ strategic reconnaissance aircraft. It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by the Lockheed Skunk Works. Clarence “Kelly” Johnson was responsible for many of the design's innovative concepts. During reconnaissance missions the SR-71 operated at high speeds and altitudes to allow it to outrace threats. If a surface-to-air missile launch was detected, the standard evasive action was simply to accelerate and outrun the missile”. – Wikipedia

Photo: A U.S. Air Force SR-71A, also known as the “Blackbird”, is put through it's paces during a test flight over Beale Air Force Base in California. The aircraft is a strategic reconnaissance plane by Lockheed and is the world's fastest and highest flying operational aircraft. (Photo by Getty Images)

Just a week before Rio de Janeiro hosts South America's first Olympics, city residents expressed mixed feelings about the cost and security of the Games, while holding out hope they will bring joy to a nation facing economic and political crises. The conflicted thoughts mirror a recent survey by the Datafolha polling group showing that half of Brazilians were opposed to holding the Games, while 63 percent think the costs of hosting the event will outweigh benefits. (Photo by Pilar Olivares/Reuters)

“MSC Fabiola is a container ship owned by Mediterranean Shipping Company (MSC), the largest such vessel ever to dock in North America. In March 2012 the ship shifted from its initial Asia-to-Europe service to begin trans-Pacific service. On March 19, 2012, Fabiola docked at the Port of Long Beach, breaking earlier records for the largest container ship at a US port, and at any North American port”. – Wikipedia

Photo: The container ship MSC Fabiola (R) is seen docked at the Port of Oakland on March 22, 2012, in Oakland, California. The MSC Fabiola is the largest container ship ever to dock at any seaport in North America with an overall length of nearly one quarter mile long. (Photo by Justin Sullivan/Getty Images)

“A snow roller is a rare meteorological phenomenon in which large snowballs are formed naturally as chunks of snow are blown along the ground by wind, picking up material along the way, in much the same way that the large snowballs used in snowmen are made”. – Wikipedia. Photo: Snow Roller. (Photo by The Daily Omnivore)

A woman walks past a painting by Jenny Saville entitled “Red Stare Head IV” on display in the Royal Academy of Arts' Summer Exhibition on June 2, 2011 in London, England. The Summer Exhibition is the world's largest open submission contemporary art show, now in its 243rd year, with over 12,000 entries received from 27 countries. The exhibition features over 1100 works of art including: painting, sculpture, photography, architecture and film, it officially opens to the public on June 7, 2011. (Photo by Oli Scarff/Getty Images)