A wedding couple poses for a photographer during a wedding photo shoot March 9, 2011 in Hanoi, Vietnam. Its is traditional for middle and upper class Vietnamese couples do a wedding fashion shoot posing for wedding portraits a few weeks before the wedding so that a wedding photo book is produced. (Photo by Paula Bronstein /Getty Images)

Jo-Anne McArthur’s book of photographs puts the spotlight on ethics of zoos around the world. Accompanied by essays by Born Free Foundation’s Virginia McKenna and philosopher Lori Gruen, the images and stories are also shared online through “A Year of Captivity”. Here: Asian Elephant, Denmark, 2016. (Photo by Jo-Anne McArthur/Born Free Foundation/The Guardian)

An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)

28 year old Rupa has her hair shaven to donate to the Gods at the Thiruthani Murugan Temple November 10, 2016 in Thiruttani, India. Rupa donated her hair with the wish that her daughter's illness is cured. The process of shaving ones hair and donating it to the Gods is known as tonsuring. It is common for Hindu believers to tonsure their hair at a temple as a young child, and also to celebrate a wish coming true, such as the birth of a baby or the curing of an illness. The “temple hair”, as it's known, is then auctioned off to a processing plant and then sold as pricey wigs and weaves in the US, Europe and Africa. (Photo by Allison Joyce/Getty Images)

A student falls asleep as she holds a book containing a portrait of China's late chairman Mao Zedong during a lesson at the Democracy Elementary and Middle School in Sitong town, Henan province December 3, 2013. In a remote part of central China, the day starts at the Democracy Elementary and Middle School with a pre-dawn jog, some revolutionary songs and then an activity long since forgotten at other schools: reciting quotations from Mao Zedong's famed “Little Red Book”. While the ruling Communist Party that Mao led continues to hold him in esteem as the leader of the Communist Revolution, his radical policies and teachings have been largely shelved since his death in 1976 in favour of a pro-market approach that has turned China from a backwater into the world's second biggest economy. The 120th anniversary of Mao's birth is on December 26, 2013. (Photo by Carlos Barria/Reuters)

Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)

Lasha Pataraia pulls a truck, which weighs 8,250kg (8 tons), with his ear during an event to break the Guinness Book of World Records in Rustavi, outside Tbilisi November 29, 2012. The 32-year-old broke a Guinness record after he managed to pull the truck with his ear for 21,50 metres (70.5 feet), according to organisers. (Photo by Irakli Gedenidze/Reuters)

Afghans shout anti-U.S. slogans as they burn tires and block a highway during a protest in reaction to a small American church's plan to burn copies of the Quran, at Jalalabad, east of Kabul, Afghanistan, Friday, September 10, 2010. Religious and political leaders across the Muslim world welcomed a decision by the church to suspend its plans to torch copies of their holy book but some said Friday the damage has already been done. (Photo by Rahmat Gul/AP Photo)