Russia-backed separatists stand at the site of the crashed Malaysia Airlines Flight 17 plane, near the village of Hrabove, eastern Ukraine, Thursday, July 16, 2015. The fighters said they have arrived to protect the media and make sure the MH17 crash site is clear of ammunition and mines. A year since a Malaysia Airlines Boeing 777 was blown out of the sky over war-ravaged eastern Ukraine, killing 298 people, there has been little official word of progress in determining what brought down Flight MH17. (Photo by Antoine E. R. Delaunay/AP Photo)

The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

Members of the media film as a ranger performs a post mortem on the carcass of a rhino after it was killed for its horn by poachers at the Kruger national park in Mpumalanga province August 27, 2014. Rhino poachers in South Africa now risk giving themselves away when they shoot thanks to a high-tech, gunfire-detection system being piloted in the country's flagship Kruger National Park. The stakes are high, for rhinos are being slain in escalating numbers for their prized horns, alarming both conservationists and the government since wildlife in South Africa is an important tourist draw. (Photo by Siphiwe Sibeko/Reuters)

Birds sit on the back of a zebra in the Nairobi National Park, near Nairobi, Kenya, November 21, 2018. (Photo by Baz Ratner/Reuters)

A man selling bags of water is seen at a taxi parking bay lined with campaign posters in the district of Lingwala in Kinshasa on December 18, 2018. Democratic Republic of Congo goes to the polls on December 23, 2018 in elections which could see the country emerge from 17 years of conflict-ridden rule under controversial President Joseph Kabila. (Photo by John Wessels/AFP Photo)

Lion dance with LED lights, perform on the glass deck of the King Power Mahanakhon building, currently Thailand's tallest at 314 meters (1,030 feet) tall, Bangkok, Thailand, Monday, February 4, 2019. Chinese will celebrate the lunar new year on Feb. 5 this year which marks the Year of the Pig in the Chinese zodiac. (Photo by Sakchai Lalit/AP Photo)

A female brown bear with cubs fishing on Lake Kronotskoye as part of the South Kamchatka, Russia on Sanctuary, August 13, 2017. (Photo by TASS/Barcroft Images)

Fans react as they watch HBO's “Game of Thrones” series finale at a viewing party at Brennan's bar in Marina del Rey, California, May 19, 2019. (Photo by Robyn Beck/AFP Photo)