A passenger (L) gets inside a decorated matatu as other passengers wait for it to fill at night in the streets of Nairobi, Kenya, 24 March 2018. The Matatu culture is very big in Kenya, the minibuses are decorated with colorful graffiti inside and outside and most of them are equipped with TV screens, high-speed internet, and power sockets. (Photo by Daniel Irungu/EPA/EFE)

A girl walks along former railway tracks in the so- called “Tunnel of Love”, surrounded by arches of intertwined trees, near the Ukrainian village of Klevan, Rivno region, on August 6, 2018. The tunnel of about five kilometres in length is a botanical phenomenon, which became a cult place for tourists and couples in love. The tourist legend says that wishes of couples in love will come true, if the couple passes through the tunnel. (Photo by Sergei Supinsky/AFP Photo)

Tourists from the Middle East take pictures at Vrelo Bosne nature park in Ilidza near Sarajevo, Bosnia and Herzegovina, August 19, 2016. They discovered mountainous Bosnia, where half the population is Muslim, after the Arab Spring which destabilized many traditional holiday destinations such as Libya, Tunisia and Egypt. (Photo by Dado Ruvic/Reuters)

Smoke plumes rise from Mount Etna, one of the most active volcanoes in the world in Sicily, Italy on June 28, 2016. (Photo by Etna Walk/Rex Feature/Shutterstock)

In this handout photograph received from Sumukha J.N on December 15, 2016, the newly-discovered spider Eriovixia Gryffindori sits on a leaf in the Kans in India's Western Ghats. (Photo by Sumukha J.N./AFP Photo)

The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

One of the most significant challenges related to cancer in Nepal is the lack of awareness around the prognosis of the disease, as many patients, their families and even healthcare professionals consider cancer to be an incurable disease at any stage. This results in significant delays in bringing patients to hospitals, and high rates of advanced stage cancers and mortality. (Photo by Omar Havana)

A man runs after he tried to put himself on fire during a protest at a makeshift camp at the Greek-Macedonian border near the village of Idomeni on March 22, 2016. Greece will not be able to start sending refugees back to Turkey from March 20, 2016, the government said, as the country struggles to implement a key deal aimed at easing Europe's migrant crisis. The numbers are daunting: officials said as of Saturday there were 47,500 migrants in Greece, including 8,200 on the islands and 10,500 massed at the Idomeni camp on the Macedonian border. (Photo by Andrej Isakovic/AFP Photo)