Del Mar firefighters roll up hose after a day fighting wildfires Wednesday, May 14, 2014, in Carlsbad, Calif. More wildfires broke out Wednesday in San Diego County, threatening homes in Carlsbad and forcing the evacuations of military housing and an elementary school at Camp Pendleton. (Photo by AP Photo)

The 26th annual National Geographic Traveler Photo Contest is now accepting submissions. Official categories include: “Travel Portraits”, “Outdoor Scenes”, “Sense of Place” and “Spontaneous Moments”. The contest is accepting entries until June 30. Photo: “Forest lights”. Aurora Borealis over the forest of the Pyhae Luosto National Park, Finland. (Photo and caption by Nicholas Roemmelt/National Geographic Traveler Photo Contest)

A member of the USA Knights team is seen wearing a face-like helmet shield during the International Medieval Combat championships at the castle of Belmonte, May 4, 2014, in Belmonte, Spain. The steel armor the knights wear can cost up to $10,000 and weigh 80 pounds. (Photo by Juan Naharro Gimenez/Getty Images)

“My goal was to capture the image of a storm that emulated an atomic explosion”, Dobrowner says of this picture. Here: “Monsoon”, Lordsburg, N.M., 2010. (Photo by Roger Hill)

U.S. Marines kick in a door while securing a building next to the main hospital in central Baghdad April 15, 2003, which will be used as a temporary Iraqi police headquarters. (Photo by Jerry Lampen/Reuters)

The Queen Elizabeth Tower (Big Ben) is reflected in a puddle as a cyclist rides by in London, on 27 June 2016. Britain began preparations to leave the European Union on Monday but said it would not be rushed into a quick exit, as markets plunged in the wake of a seismic referendum despite attempts to calm jitters. (Photo by Leon Neal/AFP Photo)

Sister Rebecca Leis pours low-gluten alter bread batter into a machine that bakes the thin bread at the Benedictine Sisters of Perpetual Adoration monastery in Clyde, Missouri, December 18, 2014. The Sisters have made communion wafers since 1910 and began making a low-gluten version in 2003 and have gone from 143 customers in 2004 to more than 11,000 customers from around the world. (Photo by Dave Kaup/Reuters)