A woman carrying a basket of papayas while walking through a vegetable market in Bangkok, Thailand November 11, 2011. (Photo by Kerek Wongsa/Reuters)

A man poses in front of a portrait of late Chinese Chairman Mao Zedong during the opening of an exhibition of Mao related art in Beijing, China, September 8, 2016. (Photo by Thomas Peter/Reuters)

Yala national park, Sri Lanka. Category: Action. “The daylight was fading and I was scanning the bush for a leopard. Then, I saw this garden lizard and a common bronzeback snake in the road. When the snake struck, the lizard performed amazing acrobatics to avoid it. The snake didn’t enjoy the extra attention from the crowd of jeeps. The distraction gave the lizard the chance to live another day”. (Photo by Sajith Buddikha Withanage/National Geographic Traveller UK)

Respect, Kronotsky nature reserve, Russia. The photographer’s cat, Ryska – her name means little lynx in Russian – stands outside their cabin and with aggressive posturing warns off a fox. In winter, foxes would regularly visit the cabin searching for food. If one peered in at the window, possible when the snow was deep, Ryska would sit on the other side, fur raised, and growl. When outside, she would hold her ground. The foxes were not always frightened and so encounters could be a sort of dance. (Photo by Igor Shpilenok/Unforgettable Behaviour/NHM)

A child dressed as a Roman centurion poses during a parade to mark the anniversary of the foundation of Rome in 753 BC, on April 23, 2017 in Rome. (Photo by Alberto Pizzoli/AFP Photo)

A conductor (C) collects fares from candy floss sellers as they travel in a tram to a marketplace early morning in Kolkata, India, December 23, 2015. (Photo by Rupak De Chowdhuri/Reuters)

A person viewing the Northern lights over the lava landscape, Reykjanes Peninsula, Iceland. (Photo by Arctic-Images/Getty Images)

Barrier tape is tied around 15-month-old Shivani's ankle to prevent her from running away, while her mother Sarta Kalara works at a construction site nearby, in Ahmedabad, India, April 19, 2016. Kalara says she has no option but to tether her daughter Shivani to a stone despite her crying, while she and her husband work for 250 rupees ($3.8) each a shift digging holes for electricity cables in the city of Ahmedabad. There are about 40 million construction workers in India, at least one in five of them women, and the majority poor migrants who shift from site to site, building infrastructure for India's booming cities. Across the country it is not uncommon to see young children rolling in the sand and mud as their parents carry bricks or dig for new roads or luxury houses. (Photo by Amit Dave/Reuters)