Israeli soldiers detain a protester during a demonstration by Palestinians protesting against the Israeli-built West Bank separation barrier and calling for the right of return for Palestinian refugees, in the northern West Bank city of Tulkarem, on May 31, 2014. (AP Photo/Nasser Ishtayeh)

A pilot steers his helicopter at night over Rio de Janeiro, Brazil, less than two weeks before the start of the Rio 2016 Olympic Games, July 23, 2016. Picture taken July 23, 2016. (Photo by Pawel Kopczynski/Reuters)

German flying ace Baron Manfred von Richthofen (1892–1918) also known as The Red Baron with his dog Moritz, circa 1916.

A flock of sheep huddles together while snow spindrift is whipped up by strong winds in Swaledale, North Yorkshire, UK on March 17, 2017. (Photo by Paul Kingston/NNP North News & Pictures Ltd)

Isabella Busse, 6, walks through floodwater near the Seal Beach Pier during a storm in Seal Beach, Calif., Sunday, January 22, 2017. The heavy downpour on Sunday drenched Orange County in one of the heaviest storms of the year. Fast-moving floodwaters swept through California mountain communities and residents fled homes below hillsides scarred by wildfires as the third in the latest series of storms brought a deluge Sunday and warnings about damaging mudslides. (Photo by Ana Venegas/The Orange County Register via AP Photo)

Performers dressed as Ded Moroz, the equivalent of Santa Claus, and his granddaughter Snegurochka (Snow Maiden) take on shoe covers as they visit the Republican Scientific and Practical Centre of Pediatric Surgery in Minsk, Belarus, December 28, 2016. (Photo by Vasily Fedosenko/Reuters)

“Touring the Koko-en Gardens adjacent to the Himeji castle was an unexpected highlight of our visit”, wrote Jeff Solar, 64, of Silver Spring, Md., about his trip to Japan. “The fall colors were outstanding and the gardens were both amazing and a bargain (just a few Yen added to the cost of the Himeji Castle admission)”. (Photo by Jeff Solar/2017 Washington Post Travel Photo Contest)

A volcanic eruption at Mount Etna’s Vorgaine crater in Sicily, Italy on December 3, 2015. (Photo by Marco Restivo/Barcroft Media)