A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

For more than 2,000 years, women from the Baiga tribe in the highland district of Dindori, in central India’s Madhya Pradesh state, have been tattooed. Sumintra, 25, from Bona village, has the markings across her forehead, legs and arms. The women who work as tattoo artists are knowledgable about the different types of designs and pigments preferred by various tribes, and their meanings are passed to them by their mothers. The tattooing ‘season’ begins with the approach of winter. (Photo by Ronny Sen/WaterAid/The Guardian)

A protestor gestures during clashes with police during protests against planned fuel price hikes on March 27, 2012 in Jakarta, Indonesia. Thousands of Indonesians students in big cities all over the county gathered to protest the governments plans to increase the price of subsidized fuel by 30 percent. The Indonesian parliament is currently debating the fuel hikes which would go into effect March 25, 2012 if approved. (Photo by Ulet Ifansasti/Getty Images)

“A prototype lunar lander was destroyed on August 9, 2012, at Kennedy Space Center during its first free flight”. – James Dean via Florida Today

Photo: Morpheus Ground Level Hot Fire. Photo Date: April 2nd 2012. Location: VTB Flight Complex; Photographer: Joe Bibby

A Thai man smokes a cigarette as he sits in the flooded streets October 10, 2011 in Ayutthaya, Thailand. Around 200 factories closed in the central Thai province of Ayutthaya because of flooding, which is posing a threat to Bangkok as well. Over 260 people have died in flood-related incidents since late July according to the Department of Disaster Prevention and Mitigation. Some areas of the country are experiencing the worst flooding in 50 years, mainly in the centre, north and northeast. (Photo by Paula Bronstein /Getty Images)

“Burning Man is a week-long annual event held in the Black Rock Desert in northern Nevada, in the United States. The event starts on the Monday before the American Labor Day holiday, and ends on the holiday itself. It takes its name from the ritual burning of a large wooden effigy on Saturday evening. The event is described by many participants as an experiment in community, radical self-expression, and radical self-reliance”. – Wikipedia

Photo: A fireball billows up from a 52-foot tall wooden man as it goes up in flames September 2, 2000 during the15th annual Burning Man festival in the Black Rock Desert near Gerlach, Nevada. Despite high winds, dust storms, and a bit of rain, some 27,000 people camped out on a remote desert playa, or dry lake, for the week-long counter-cultural celebration of art and “radical self-expression”. (Photo by David McNew/Newsmakers)

Pig Felix of physiotherapist Daan Vermeulen lies amid elderly people in a senior care facility on April 12, 2011 in Gelsenkirchen, Germany. (Photo by Ralph Orlowski/Getty Images)

“A Double Eagle is a gold coin of the United States with a denomination of $20. (Its gold content of 0.9675 troy oz was worth $20 at the then official price of $20.67/oz). The coins are made from a 90% gold (0.900 fine = 21.6 kt) and 10% copper alloy”. – Wikipedia

Photo: A “Double Eagle” gold twenty dollar coin is displayed above a catalogue picture showing the reverse side of the coin at Goldsmith's Hall on March 2, 2012 in London, England. Nearly half a million of these coins were originally minted in the midst of the Great Depression in the US. Only 13 are known today after the rest were melted down before they ever left the US Mint, sacrificed as part of a strategy to stabalise the American economy. In 2002 a Double Eagle sold at auction for $7.6 million. (Photo by Peter Macdiarmid/Getty Images)