A sunflower “smiles” in a field in Tokyo on August 7, 2014. Some 20,000 sunflowers were enjoyed by visitors to the area this week. (Photo by Yoshikazu Tsuno/AFP Photo)

An Indian Runner duck searches for food on a snow-covered meadow in Aitrang, southern Germany, Wednesday. April 19, 2017. (Photo by Karl-Josef Hildenbrand/DPA via AP Photo)

Snow falls as a woman walks her dog in the village of Podolye, 70 kilometers (43 miles) east of St. Petersburg, Russia, early Thursday, May 11, 2017. North winds brought snow to the east of the St. Petersburg region. (Photo by Dmitri Lovetsky/AP Photo)

A woman looks at a handgun at the Glock booth at the Shooting Hunting and Outdoor Trade Show, Tuesday, January 19, 2016, in Las Vegas. The SHOT Show, the world's largest annual trade show for shooting, hunting and law enforcement professionals, runs through January 23 and is expected to feature 1,600 exhibitors showing off their latest products and services to more than 62,000 attendees. (Photo by John Locher/AP Photo)

A selection of work by four photojournalists who have won grants of $10,000 and editorial support from the agency. Here: “Chasing Winter” by Katie Orlinksy. In late summer and early autumn polar bears flock to the native village of Kaktovik in the Alaskan Arctic to eat at “the boneyard” – the remains of whales annually hunted by the community. (Photo by Katie Orlinsky/Getty Images)

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

A fireball erupts from a 16-inch gun on the battleship USS Wisconsin during a live fire exercise in the Persian Gulf, October 13, 1990. The ship is in the Gulf as part of Operation Desert Shield. (Photo by John Gaps III/AP Photo)

A blurred panaroma of Roemerberg historic center is reflected in a soap bubble in Frankfurt am Main, Germany, 09 July 2015. (Photo by Frank Rumpenhorst/EPA)