Two dummy tanks being pushed along a road by German soldiers. (Photo by Hulton Archive/Getty Images). Circa 1925

A Republican farmer defending a farm on the outskirts of Irun against Nationalist forces during the Spanish Civil War, 6th September 1936. A comrade lies dead by his side. (Photo by Keystone/Hulton Archive/Getty Images)

Winner of the National Park Foundation's photo contest; Honorable Mention: Fan Favorite. Grand Canyon National Park, Arizona. Three friends enjoy sunrise over the Grand Canyon. (Photo by Peter Blanchard)

A British soldier from 3 Commando Brigade looks through the sight of his sniper rifle at Camp Gibraltar February 24, 2003 near Kuwait City, Kuwait. (Photo by Ian Waldie/Getty Images)

The summit of one of Europe's tallest mountains glows like the flame of a candle as the sun rises on a clear morning. The Matterhorn, famous for appearing on bars of Toblerone chocolate bars, reflects the vivid orange light at 5.37am. (Photo by Margarethe Jaeger/Solent News & Photo Agency)

Camelot, with rider Kris Anderson, wins an exhibition race billed as “The Cameltonian” at the Meadowlands Race Track in East Rutherford, New Jersey June 21, 2014. Run by Hedrick's Promotions in Nickerson, Kansas, this is the third year the race has been run at the track, in tandem with an ostrich race. (Photo by Ray Stubblebine/Reuters)

An aerial view taken with a drone shows the autumnally colored Fuerst-Pueckler-Park near Cottbus, eastern Germany, Saturday, October 29, 2016. The park, composed with great sensitivity in the 19th century by Prince Hermann von Pueckler-Muskau, is considered as one of the last great German landscape gardens. (Photo by Patrick Pleul/DPA via AP Photo)

Malabon Zoo owner Manny Tangco holds a full-grown but very small rooster named “Small But Terrible” from Malaysia to compare it with the giant red rooster from France named “Mr. Universe” as they are shown to the media as part of the “Roosters of the World” exhibition to celebrate the “Red Fire Rooster” in the Chinese lunar calendar Friday, January 27, 2017 in suburban Malabon city north of Manila, Philippines. The Roosters of the World exhibition features roosters from countries as the United States, Japan, United Kingdom, France, China, Malaysia, Indonesia and Poland. (Photo by Bullit Marquez/AP Photo)