A thirty-year-old Dutch demonstrator displays a sign that reads: “Glad to be Gay” during a gay people march in Frankfurt, Germany on Saturday, July 28, 1979 which ended a week long homosexual meeting. Hundreds of homosexual converged for a week of movies, theater, rock concerts and workshops on gay rights. (Photo by Rolf Boehm/AP Photo)

A protester performs the symbolic death of a student demonstrator during a march near Congress where Chile's President Michelle Bachelet gives her annual address in Valparaiso, Chile, Thursday, May 21, 2015. Demonstrators are protesting the death of two students killed during an education reform march last week in Valparaiso and demanding more involvement in education reform. (Photo by Luis Hidalgo/AP Photo)

Young cheetahs eat meat at The Cheetah Conservation Fund (CCF) center in Otjiwarongo, Namibia, on August 13, 2013. The CCF started breeding Anatolian livestock dogs to promote cheetah-friendly farming after some 10,000 big cats – the current total worldwide population – were killed or moved off farms in the 1980s. Up to 1,000 cheetahs were being killed a year, mostly by farmers who saw them as livestock killers. But the use of dogs has slashed losses for sheep and goat farmers and led to less retaliation against the vulnerable cheetah. (Photo by Jennifer Bruce/AFP Photo)

Amateur astronomer Bill Snyder has been involved with astrophotography since 2007. Photo: The Cygnus Wall is in the southern area of NGC7000 also known as the North America Nebula. It is approximately 1800 light years from Earth, and is in the constellation Cygnus. The Wall is an energized shock front and contains the most concentrated star formations in the nebula. The size of the North America Nebula is about 4 full moons. (Photo and caption by Bill Snyder)

A model takes a selfie during rehearsal for the Moe Ho collection by designer Mengmeng He, during China Fashion Week in Beijing, March 29, 202. (Photo by Ng Han Guan/AP Photo)

A father crosses a road with his twin daughters in Shanghai, China September 28, 2018. (Photo by Aly Song/Reuters)

The Epson International Pano awards showcase the work of the best panoramic photographers from around the world. Here: “Paepalanthus at Moonlight” Veadeiros Tablelands, Brazil. (Photo by Marcio Cabral/Epson International Pano Awards 2017)

A white Bengal tiger cub plays with its mother in a zoo in the Siberian city of Novosibirsk, about 2,800 kilometers (1,750 miles) east of Moscow, Russia, Tuesday, April 21, 2015. Two blue-eyed Bengal tiger cubs were born in March to a couple of white tigers at Novosibirsk zoo. (Photo by Ilnar Salakhiev/AP Photo)