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 stunt rider jumps over spectators after the final stage of the annual ABSA Cape Epic mountain bike stage race, Cape Town, South Africa, 30 March 2014. The multi day stage race is know as the “Tour de France” of mountain biking and sees 1,200 riders riding 720km in seven days. The race includes the worlds leading professional racers along with amateur cyclists. (Photo by Kim Ludbrook/EPA)

Beachgoers watch the detonation of a 500 pound British bomb on the beach on May 19, 2014 in Wassenaar, Netherlands. The bomb was dropped by the British allied forces during the second world war over nearby Leiden where it was found on a building site. (Photo by Michel Porro/Getty Images)

“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

Buyan, a male Siberian brown bear, is given a shower by a zoo employee in his enclosure at the Royev Ruchey zoo in Russia's Siberian city of Krasnoyarsk June 24, 2014. The Siberian city has been experiencing temperatures of around 30 degrees Celsius over the last week. (Photo by Ilya Naymushin/Reuters)

The Supermoon rises over houses in Olvera, in the southern Spanish province of Cadiz, July 12, 2014. Occurring when a full moon or new moon coincides with the closest approach the moon makes to the Earth, the Supermoon results in a larger-than-usual appearance of the lunar disk. (Photo by Jon Nazca/Reuters)

Russian Tu-95MS strategic bombers fly in formation during rehearsals for the Victory Day military parade, with St. Basil's Cathedral seen in the foreground, in central Moscow May 5, 2015. Russia will celebrate the 70th anniversary of the victory over Nazi Germany in World War Two on May 9. (Photo by Tatyana Makeyeva/Reuters)

Bottlenose dolphins swim over visitors in water tank at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, southwest of Tokyo, Tuesday, July 21, 2015. Temperatures in Tokyo's metropolitan area neared around 96 degree Fahrenheit, or 35 degree Celsius, on Tuesday. (Photo by Shuji Kajiyama/AP Photo)