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)

Tommy Lindsey holds an enormous maple leaf that he found in Mount Vernon, Wash., October 28, 2013. Lindsey was walking with his family when he picked up the leaf that is more than two feet from stem to tip and more than 21 inches wide. (Photo by Frank Varga/The Skagit Valley Herald)

Women dressed in folk costumes take part in a traditional wedding ceremony in the village of Galicnik, west of Macedonia's capital Skopje, July 12, 2014. The Galicnik Wedding, a three-day traditional Macedonian wedding celebration held each “Petrovden” or St. Peter's Day, involves traditional customs, costumes, and rituals and dances that have been passed down over the centuries. (Photo by Ognen Teofilovski/Reuters)

Members of the Communist New Fourth Army on parade. Note how the modern equipment contrasts with the shoeless soldiers in the foreground. (Photo by Hulton Archive/Getty Images). 6th July 1946

A boy collects drinking water from a hand pump in Kutubdia, Bangladesh on March 30, 2016. Kutubdia is one of many islands affected by some of the fastest recorded sea-level rises in the world. The island has halved in size in 20 years. (Photo by SIipa/Rex Features/Shutterstock)

A demonstrator is carried during a rally in support of a identity check draft law and against delinquency, in Santiago, Chile April 30, 2016. (Photo by Carlos Vera/Reuters)

One of the poor families collecting firewood from the street and the burn to feel some warmth in Aleppo, Syria on August 19, 2016. (Photo by Basem Ayoubi/Imageslive/ZUMA Press/Splash News)

In this April 14, 2014 file photo, Hamamatou Harouna, 10, who lost the use of her legs to polio, crawls to the restroom on the grounds of the Catholic Church where she and hundreds of others found refuge after fleeing violence in her village, in Carnot, Central African Republic. Health authorities on Tuesday, August 25, 2020 are expected to declare the African continent free of the wild poliovirus after decades of effort, though cases of vaccine-derived polio are still sparking outbreaks of the paralyzing disease in more than a dozen countries. (Photo by Jerome Delay/AP Photo/File)