Dark clouds bearing down on the city on April 17, 2011 in Foshan, Guangdong Province of China. According to flood control authorities on Monday, gales as strong as 45.5 meters per second, accompanied by hailstorm, cloudburst and strong wind battered cities including Guangzhou, Foshan, Zhaoqing and Dongguan of south China's Guangdong Province on Sunday, has killed at least 17 people and injured 118. (Photo by ChinaFotoPress/Getty Images)

“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)

A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

Indian Runner ducks march past farm buildings at the Vergenoegd wine estate near Cape Town, South Africa, May 16, 2016. Each day, a quack squad of killer ducks are released for the first of two sorties at South Africa's Vergenoegd wine farm in Stellenbosch. Their mission – seek and destroy thousands of pests out to ruin the season's harvest. Fanning out across the vineyards, some 1,000 Indian Runner ducks hone in on their hidden targets with uncanny precision, locating the tiny white dune snails feasting on budding vines. (Photo by Mike Hutchings/Reuters)

An invalis asking alms walks past a girl posing for the picture in the center of Ukrainian capital of Kiev on August 17, 2016. (Photo by Sergei Supinsky/AFP Photo)

Anti-racist Loldiers of Odin clowns speak with police as they take to the streets against anti-immigration marchers in Tampere, Finland January 23, 2016. Police prevented the groups from confronting each other. On the northern fringes of Europe, Finland has little history of welcoming large numbers of refugees, unlike neighbouring Sweden. But as with other European countries, it is now struggling with a huge increase in asylum seekers and the authorities are wary of any anti-immigrant vigilantism. (Photo by Kalle Parkkinen/Reuters/Lehtikuva)

A woman poses with a cut-out of Vladimir Putin in the “President Cafe” in Krasnoyarsk, Siberia, Russia, April 7, 2016. Dozens of photos of Vladimir Putin, from childhood to Russian President, hang on the walls of President Cafe in a working-class area of Krasnoyarsk, a city in eastern Siberia. A life-size cut-out of Putin stands by the bar. Images of U.S. President Barack Obama, as well as leaders of Germany and Britain, greet customers in the toilets. (Photo by Ilya Naymushin/Reuters)

Most of people who have visited Bali have seen the cockfighting popular among the locals. A little-known but no less ardent hobby among Bali’s farming community is cricket fighting, or mejangkrikang. The insects face off inside bamboo tubes known as bumbung, and bets are placed on the bouts, which typically last two minutes. Here: a cricket breeder shows his two adult fighter crickets on a bamboo tubes called Bumbung. (Photo by A. A. Gde Agung/JG Photo)