Emperor penguins gathered together to keep their chicks warm in these pictures. Marine scientist Frederique Oliver snapped the protective parents in Antarctica as they huddled against the huge winds.The adorable birds have to battle temperatures on -20 degrees Celsius as well as winds of up to 40 knots on the ice. (Photo by Frederique Oliver/Caters News)

These photographs of hundreds of ducks following their leader down a river are truly mesmerizing. Rafeur Rahman of Bangladesh climbed a high bridge and saw hundreds of ducks apparently playing a game of follow the leader. More than 500 ducks live on the river, where the mosses and snails provide the perfect habitat. Here: Ducks in the river Baral in Bangladesh. (Photo by Rafeur Rahman/Caters News Agency)

“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)

Thoughts. They fly through the broad expenses of our mind, floating gracefully in midair, going into the clouds, and then reemerging once again. Some are quick and furtive, others are grand and majestic. We reflect upon them as they enter our minds, and once they leave, they are usually gone for good. However, some thoughts are different. These thoughts resemble a flock of angry birds or a swarm of hungry moths that invade your mind, slowly eating away at your sanity, strength, and desire to live. Such thoughts often plague that minds of people with Obsessive Compulsive disorder. They completely occupy their time; constantly there; ever-present. With his book sculpture, Thomas Wightman was able to accurately convey the way these thoughts consume the mind, slowly building a nest within it, resisting all attempts to drive them away.

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)

Dancer Megan changes costume as she performs in the review “Feerie” at the Moulin Rouge in Paris, France, July 3, 2018. Each show requires 1,000 outfits, all crafted in the workshops that have been supplying the Moulin Rouge for decades. Each dancer has to make between 10 and 15 costume changes per show, with about 90 seconds to complete each one before they have to be back out on stage. (Photo by Philippe Wojazer/Reuters)

First prize. Taken over Bali Barat National Park, Denpasar, Bali. Made with a GoPro Hero 2 camera. (Photo by Capungaero)

A woman reacts after she was hit with pepper spray deployed by police as they cleared a street with protesters rallying against a new national security law in Hong Kong on July 1, 2020, on the 23rd anniversary of the city's handover from Britain to China. A man found in possession of a Hong Kong independence flag became the first person to be arrested under Beijing's new national security law for the city, police said on July 1. (Photo by Dale De La Rey/AFP Photo)