Stones collected and categorised by shape (fish) are seen at the home workshop of Luigi Lineri in Zevio, near Verona, Italy, June 10, 2016. Luigi Lineri's home workshop is covered in stones – tens of thousands of them. They resemble animal heads, human faces and other forms, and the artist and poet believes may have been shaped by prehistoric humans. (Photo by Alessandro Bianchi/Reuters)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

Visitors and car enthusiasts attend the annual Goodwood Revival historic motor racing festival, celebrating a mid-twentieth century heyday of the racing circuit, near Chichester in south England, Britain, September 9, 2016. (Photo by Toby Melville/Reuters)

A sofa floats in the polluted waters of Jacarepagua Lagoon, during a press tour in Rio de Janeiro, March 9, 2015. A press tour was organised by biologist Mario Moscatelli, to call attention to pollution on the waters of the lagoons which surround the Rio 2016 Olympic Park. (Photo by Ricardo Moraes/Reuters)

British model and actress Rosie Huntington-Whiteley arrives for the Versace's fall-winter 2015/2016 Haute Couture fashion collection presented in Paris, France, Sunday, July 5, 2015. (Photo by Thibault Camus/AP Photo)

A ship builder walks past a section of the Oasis Class 3 cruise ship at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. The Oasis-class III vessel is scheduled for delivery in mid-2016. (Photo by Stephane Mahe/Reuters)

Afghan children play on the remains of a Soviet-era armored personnel carrier on the outskirts of Jalalabad on February 15, 2016. Soviet troops withdrew from Afghanistan on February 15, 1989, after ten years of fighting against Mujahidin militiamen. (Photo by Noorullah Shirzada/AFP Photo)

“Left behind” children Luo Hongni, 11 (L) and brother Luo Gan,10, carry flowers to be used as feed while doing chores in the fields on December 18, 2016 in Anshun, China. Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. (Photo by Kevin Frayer/Getty Images)