“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

South Korean soldiers participate in a winter river crossing operation in preparation for a possible North Korean attack on February 8, 2012 in Yeoju, South Korea. The Korean peninsula is the world's last Cold War frontier as stalinist North Korea and pro-western South Korea have been technically at war since the 1950-53 conflict. (Photo by Chung Sung-Jun/Getty Images)

Veterans of the Bangladesh war of liberation march past during the celebration of the country’s 45th Victory Day at the national parade ground in Dhaka December 16, 2015. (Photo by Ashikur Rahman/Reuters)

Performers dressed like Stormtroopers dance during “The Empire Strips Back: A Star Wars Burlesque Parody” in Los Angeles, California, U.S., June 1, 2018. (Photo by Mario Anzuoni/Reuters)

A performer dances during “The Empire Strips Back: A Star Wars Burlesque Parody” in Los Angeles, California, U.S., June 1, 2018. (Photo by Mario Anzuoni/Reuters)

These brave models show no fear as they pose with bears, tigers and wolves in scenes straight from the pages of a fairy tale. The snaps show the models cuddling up to the deadly animals and even taking naps with the often unpredictable creatures. Here: “Marina with a bear”. Stepan, a 700-pound grizzly bear, was adopted by a Russian couple when he was just 3 months old. (Photo by Olga Barantseva/Caters News Agency)

These frozen caves seem almost otherworldly as they daylight illuminates them. Matej Kriz’s shots reveal the beauty of the brilliant caves, but he’s also very aware of how deadly they can be. The photographer captured the amazing shots in the Vatnajokull National Park on the Breidamerkurjokull glacier tongue. Here: The ice caves, taken in the Vatnajokull National Park in Iceland, on November 11, 2017. (Photo by Matej Kriz/Caters News Agency)

Members of the 1st Tennessee wait to take part in in a demonstration of a battle during ongoing activities commemorating the 150th anniversary of the Battle of Gettysburg, Friday, June 28, 2013, at at Bushey Farm in Gettysburg, Pa. Union forces turned away a Confederate advance in the pivotal battle of the Civil War fought July 1-3, 1863, which was also the war's bloodiest conflict with more than 51,000 casualties. (Photo by Matt Rourke/AP Photo)