Brave slackliners have been pictured walking the ropes above Rio de Janeiro, Brazil on August 15, 2016, with the half a mile drop showing the city in all its glory. The stunning shots show the daredevils tread across an eighty-two-foot-long high line on Pedra da Gvea mountain with an amazing sunrise illuminating the city landscape behind. (Photo by Rafael Moura/Caters News Agency)

“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

Little owl chicks in Northumberland, UK on August 19, 2018. Strutting up and down and barrelling through the air, these Little Owl chicks will soon be fending for themselves. The intense little birds were snapped by wildlife photographer Bill Doherty in his native Northumberland. The chicks have about seven or eight weeks to learn their survival skills before their parents drive them away to fend for themselves. (Photo by Bill Doherty/South West News Service)

A rabbit fails to jump over an obstacle during a rabbit track and field competition on the sidelines of a hunting exhibition in Kromeriz, about 60 km east of Prague, on April 1, 2017. Circa 100 rabbits took part in the competition, including disciplines as long jump, high jump and running on a flat track. (Photo by Radek Mica/AFP Photo)

16-year-old panda, Ye Ye, rests in an enclosure at the Wolong Nature Reserve, a conservation center that trains pandas for release into the wild. This image was published in the August 2016 National Geographic magazine as part of the “Pandas Gone Wild” story. (Photo by Ami Vitale/National Geographic Creative)

Nur Elita, an Acehnese woman, screams during caning as part of her sentence in the courtyard of Baiturrahman mosque in Banda Aceh, Indonesia's Aceh province December 28, 2015. Nur Elita received five strokes of the cane for having pre-marital s*x with her boyfriend, according to local media. Aceh is the only province in Indonesia, the world's most populous Muslim country, where Islamic law is implemented, according to local media. (Photo by Junaidi Hanafiah/Reuters)

“Kids of Sapa”. Four little beautiful Hmong girls from Lao Chai Village, near Sapa, Vietnam. (Photo and caption by Felipe Hanower/National Geographic Traveler Photo Contest)

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)