“When I was 8 years old, my parents paid a smuggler to take me across the Himalayas, a weekslong walk over the mountains from Tibet to India. It was a trek that tens of thousands of other Tibetans have taken since the Dalai Lama fled a failed 1959 uprising against Chinese rule. My parents must have had their reasons to send me here; they must have had the best of intentions. But 18 years later, I still don't know why they did it. They are not political people. They are small farmers who raise barley and a few yak in a rural area not far from Lhasa, the Tibetan capital. I have not seen them since I left...”. – Tsering Topgyal via The Associated Press. (Photo by Tsering Topgyal/AP Photo)

“Two Brothers”. We found about 20 lions eating a buffalo. When the male leaved the group we anticipated him to take photos. It is 8AM, light is perfect and the position too. The lion stops and looks down from the hill, another lion is coming up, it stiffens, I think that will be a fight, i'm tense, the camera is OK, the shots previously made perfect. The two meet, looking directly into their eyes, they sniff, rub against their heads, the tension drops, they start walking with the same step as when they were puppies, they are two brothers. Photo location: Masai Mara, Kenya. (Photo and caption by Massimo Mei/National Geographic Photo Contest)

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)

In this August 24, 2018 photo, Changlair Aristide pauses for a portrait, wearing his protective clothing, including an old U.N. peacekeeper's jacket he found in the trash, before scavenging the Truitier landfill in the Cite Soleil slum of Port-au-Prince, Haiti. Before 2004, Aristide recalled having enough money to splurge on shoes, T-shirts and pants, but this year he could not buy his kids anything new for the school year. “Life is like that, up and down”, Aristide said. “They'll go to school anyway, even if I have to sell my pig. I love them”. (Photo by Dieu Nalio Chery/AP Photo)

Guardian of the Mangroves – Overall Winner. Tanya Houppermans, Cuba. A curious American crocodile (Crocodylus acutus) swims right up to Tanya, at Gardens of the Queen (Jardines De La Reina), an archipelago off the coast of Cuba. It has been strictly protected since 1996, and is one of the most untouched marine ecosystems in the world. ‍ “The healthy population of American crocodiles is down to the pristine condition of the mangroves and I wanted to capture close ups of this gentle giant in its natural habitat. I hope this image can illustrate that protecting areas like this is so critical”. (Photo by Tanya Griffin Houppermans/Mangrove Photographer of the Year)

Pedestrians cover their face as they walk along the dusty road in Kathmandu, Nepal February 27, 2017. Nepal has forced 2,500 old vehicles off roads in its capital city of Kathmandu, part of a fight against alarming air pollution levels that have hit nine times World Health Organisation (WHO) limits. Air pollution has been a chronic problem in rapidly growing Kathmandu, which sits in a Himalayan valley and is home to more than 3mn people. (Photo by Navesh Chitrakar/Reuters)

Ali Asair, who has left his family behind and traveled hundreds of kilometers in search for a pasture for his animals, attends to his camel in a pastoralists' settlement in the Bandarbeyla district in Somalia's semi-autonomous region of Puntland, Somalia, 24 March 2017. According to media reports, the United Nations says only 31 percent of 864 million US dollars appeal for a drought-hit Somalia is funded. The UN said the world is facing the largest humanitarian crisis since 1945, adding that more than 20 million people are facing the threat of famine in Somalia, Yemen, South Sudan and Nigeria and 1.4 million children could die from starvation this year. (Photo by Dai Kurokawa/EPA)

A photo made available on 14 March 2016 shows a Thai villager takes selfie photograph on drought parched land at the dried up Mae Chang reservoir in Lampang province, northern Thailand, 12 March 2016. The ruined village including ancient temple had been underwater for 34 years since the Mae Chang reservoir was built in 1982, the area has now re-emerged after water in the reservoir dried up caused by the severe drought. Thailand is facing the worst drought in decades hardest hit by El Nino phenomenon combined with seasonal hot weather. (Photo by Rungroj Yongrit/EPA)