Baka pygmies in their forest home preparing food in, Sangha Forest, Central African Republic, February 2016. Here, in their forest home, traditional life continues in the face of multiplying challenges ranging from poachers, to ill health. Deep in the rainforests of central Africa lives one of the world’s most mysterious tribes. (Photo by Susan Schulman/Barcroft Images)

A busy rush hour sees thousands of commuters climbing on board a train – as well as holding onto its sides and sitting on the roof before it speeds off. Men, women and children climb and are pulled up onto the roof of the train, which is around 12ft (3.6m) high, as they try to find themselves a space. With no seats available inside, many commuters decide to take the risk and choose a rooftop view for their journey out of Dhaka city, in Bangladesh. (Photo by Yousuf Tushar/Solent News & Photo Agency)

In this photo taken on Saturday, April 22, 2017, a drawing “King for a day” is made on the back of a muddy truck by artist Nikita Golubev in Moscow, Russia. The grimy trucks traversing the polluted and dusty streets of Moscow have inspired Golubev to use white vans and trucks as his canvas to create this ephemeral street art and signs his drawings Pro Boy Nick. (Photo by Pavel Golovkin/AP Photo)

Record snowfall in the Sahara Desert near the town of Ain Sefra in Algeria on January 21, 2017. (Photo by Geoff Robinson/Rex Features/Shutterstock)

Ben Thouard, 29, regularly dives into the crystal clear waters of Teahupoo, Tahiti's most famous surf break, to snap the empty waves. He stands in the water scouting out particular shapes and the right swell direction and shoots most of his pictures during the golden hours of sunrise and sunset. Here: A shot of a wave crashing down into the ocean in the clear waters of Teahupoo. (Photo by Ben Thouard/Caters News)

A female forest guard carries a tranquillizer gun in the Gir National Park and Wildlife Sanctuary in Sasan, in Gujarat December 2, 2014. The sanctuary, which is home to Asiatic lions in India, has an area of 1,412 sq km in which female guards were employed for the first time in India in 2007. The guards fetch a monthly salary of around $148 for working almost 12 hours a day, six days a week, said one of the female guards. (Photo by Anindito Mukherjee/Reuters)

Tourists use a selfie stick on the Trocadero Square, with the Eiffel Tower in background, in Paris, Tuesday, January 6, 2015. Selfie sticks have become popular among tourists because you don't have to ask strangers to take your picture, and you can capture a wide view in a selfie without showing your arm. But some people find selfie sticks obnoxious, arguing that they detract from the travel experience. (Photo by Remy de la Mauviniere/AP Photo)

Isabella Santiago of Venezuela (C) is kissed by runner-ups after she was crowned Miss International Queen 2014 at the transgender/transsexual beauty pageant in Pattaya November 7, 2014. Some 22 contestants from 18 countries, all born male, competed in the week-long event for the crown of Miss International Queen. (Photo by Athit Perawongmetha/Reuters)