A handout photograph provided by Brian Kubicki of Costa Rican Amphibian Research Center on 26 April 2016 shows a “Crystal frog”, Hyalinobatrachium dianae (H. diane). This frog was discovered by US biologist Brian Kubicki and Costa Ricans Stanley Salazar and Robert Puschendorf in a rainy forest of Costa Rican caribbean after 40 years without notice of any new example of this kind. (Photo by Brian Kubicki/EPA/Costa Rican Amphibian Research Center)

A performer takes part in a night parade to celebrate Chinese New Year in Hong Kong Friday, February 16, 2018. The Lunar New Year this year marks the Year of the Dog in the Chinese calendar. (Photo by Vincent Yu/AP Photo)

A leopard runs to at people as they run for cover in Katmandu, Nepal, on April 10, 2013. According to reports, 15 people were injured including three policemen and two officials from the Department of Forest. The leopard was later killed with the help of Nepalese policemen and local media. (Photo by Niranjan Shrestha/Associated Press)

ATTENTION: VISUAL COVERAGE OF SCENES OF INJURY AND DEATH

Images are projected onto the Empire State Building as part of an endangered species projection to raise awareness, in New York August 1, 2015. (Photo by Eduardo Munoz/Reuters)

Alisa, 10, gets a kiss from one of the wolves her family tamed in the village of Zacherevye, Belarus, on August 17, 2014. (Photo by Sergei Gapon/AFP Photo)

A woman takes a selfie in front of a Lunar New Year display featuring sheep at a shopping mall in Hong Kong, February 13, 2015. (Photo by Bobby Yip/Reuters)

The Perseid Meteor Shower seen over The Scorhill Stone Circle in Dartmoor, Devon on August 2, 2016. (Photo by John Baker/SWNS.com)

Visitors are seen inside a newly opened bookstore in Chongqing, China on January 29, 2019. Covering an area of 1,400 square meters, the Zhongshuge Bookstore in Chongqing attracts readers with its creative decor. (Photo by Reuters/China Stringer Network)