A visitor takes pictures with a smartphone of an artwork entitled “Blue Europe, 2015” by Chinese artist Liu Bolin, on display during the exhibition “Visible Invisible” at the Mudec Museum in Milan on May 14, 2019. Liu Bolin known as “the invisible man” for his photographic self-portraits, focused on a body-painting blending with the surrounding area. (Photo by Miguel Medina/AFP Photo)

Performers on boats take part in the Qintong Boat Festival at Qin Lake National Wetland Park on April 6, 2019 in Taizhou, Jiangsu Province of China. The boat festival is held around the Qingming Festival every year, and up to 10,000 participants from nearby villages and towns, with more than 500 boats, took part in the event this year. (Photo by Tang Dehong/VCG via Getty Images)

A serviceman kisses the main icon for the Russian Armed Forces' main cathedral, delivered at the Church of Our Lady the Healer in Rostov-On-Don, Russia on May 15, 2018. The Russian Armed Forces' main cathedral is to be built in Patriot Military Park in Kubinka outside Moscow by 2020, the year of the 75th anniversary of the victory of the Soviet Red Army over Nazi Germany in the 1941-45 Great Patriotic War, the Eastern Front of World War II. (Photo by Valery Matytsin/TASS)

Same-sеx marriage supporters kiss outside the Legislative Yuan Friday, May 17, 2019, in Taipei, Taiwan after the legislature passed a law allowing same-sеx marriage in a first for Asia. The vote Friday allows same-sеx couples full legal marriage rights, including in areas such as taxes, insurance and child custody. (Photo by Chiang Ying-ying/AP Photo)

Kambeba Indian, Dream Braga, 18, aims his arrow in a jungle near the village Tres Unidos, Amazon state May 9, 2015. Dream Braga has been shooting fish with a bow and arrow for most of his life. In the Amazonian village where he grew up, that was what kids did for food and fun. He participated in the Indigenous Archery Project which recruits Amazon native children to compete with modern archery equipment and try for a place on the national team, with the 2016 Olympics in Rio de Janeiro as their ultimate goal. After training with Olympic coaches for three months, he has now been promoted to Brazil's national team. (Photo by Bruno Kelly/Reuters)

Miners work extremely long days under the hot sun and the hours are often longer in illegal mines in Ghana, West Africa, 2014. An Australian photographer has captured the harsh reality of illegal mining under the unforgiving sun with these Ghanaian miners. (Photo by Heidi Woodman/Barcroft Images)

Music student Daniele Gonzalez, (centre row, L), and Australian musician Susie Park from the Minnesota Orchestra (centre row, 2nd L), react during a rehearsal in Havana, May 15, 2015. The Minnesota Orchestra will offer two concerts in Havana and is the first major U.S. orchestra to play in Cuba since 1999. The trip cost nearly $1 million. It was underwritten by Marilyn Carlson Nelson, an heir to the Carlson hotel company fortune, and her husband Glen. The U.S. government gave special permission for a direct charter flight from Minneapolis to Havana for the event, putting 4 tons of equipment and 160 people on an Airbus 330. (Photo by Alexandre Meneghini/Reuters)

In this handout photograph received from the Delhi Police at the scene of the incident, an Indian schoolboy is confronted by a white tiger inside its enclosure at the Delhi Zoo in New Delhi on September 23, 2014. A white tiger on September 23 attacked and killed a schoolboy who appeared to have jumped or fallen into its enclosure at the zoo in the Indian capital, witnesses said. (Photo by AFP Photo/Delhi Police)