A dog welcomes a volunteer at the “Ping An A Fu” (“Safe and Happy”) Homeless Animals Rescue Center on September 11, 2006 in Nanjing of Jiangsu Province, China. (Photo by China Photos/Getty Images)

A French riot police officer is surrounded by flames, during a demonstration against the controversial labour reforms of the French government in Paris on September 15, 2016. Opponents of France's controversial labour reforms took to the streets on September 15, 2016 for the 14th time in six months in a last-ditch bid to quash the measures that lost the Socialist government crucial support on the left. Scores of flights in and out of France were cancelled as air traffic controllers went on strike to try to force the government to repeal the changes that became law in July. (Photo by Thomas Samson/AFP Photo)

Skeleton bodypainting in Chimbu tribe. Village Mindima, Simbu (a Highlands Region province in Papua New Guinea), September 14, 2009. (Photo by Rita Willaert; Source: Flickr)

A portrait of Eric Abidal of Lyon prior to the UEFA Champions League Group D match between Olympique Lyonnais and Manchester United at the Municipal de Garland Stadium on September 15, 2004 in Lyon, France.

Models promote a condom brand at the first Shenzhen s*x Culture Festival on September 21, 2007 in Shenzhen of Guangdong Province, China. The festival aims to increase awareness about reproductive health and popularise s*x education. (Photo by China Photos/Getty Images)

A tanker airplane drops fire retardant on a wildfire on September 1, 2011 in Graford, Texas. More than 6,500 acres and more than 45 homes in the area have burned since Tuesday as wildfires sweep through parts of Texas and Oklahoma. (Photo by Tom Pennington/Getty Images)

The Royal Air Force Red Arrows perform the “Gypo Split” during their first public aerobatic display since the tragic death of Flt Lt Jon Egging on September 2, 2011 in Chatsworth, England. (Photo by Christopher Furlong/Getty Images)

Athletes of single bamboo drifting perform during the 9th National Traditional Games of Ethnic Minorities of the People's Republic of China on September 11, 2011 in Guiyang, China. (Photo by Feng Li/Getty Images)