“Two Brothers”. We found about 20 lions eating a buffalo. When the male leaved the group we anticipated him to take photos. It is 8AM, light is perfect and the position too. The lion stops and looks down from the hill, another lion is coming up, it stiffens, I think that will be a fight, i'm tense, the camera is OK, the shots previously made perfect. The two meet, looking directly into their eyes, they sniff, rub against their heads, the tension drops, they start walking with the same step as when they were puppies, they are two brothers. Photo location: Masai Mara, Kenya. (Photo and caption by Massimo Mei/National Geographic Photo Contest)

Astronaut Edward H. White II, pilot for the Gemini-Titan 4 (GT-4) spaceflight, floats in the zero-gravity of space during the third revolution of the GT-4 spacecraft on June 3, 1965. White wears a specially designed spacesuit. His face is shaded by a gold-plated visor to protect him from unfiltered rays of the sun. In his right hand he carries a Hand-Held Self-Maneuvering Unit (HHSMU) that gives him control over his movements in space. White also wears an emergency oxygen chest pack; and he carries a camera mounted on the HHSMU for taking pictures of the sky, Earth and the GT-4 spacecraft. He is secured to the spacecraft by a 25-feet umbilical line and a 23-feet tether line. Both lines are wrapped together in gold tape to form one cord. Astronaut James A. McDivitt, command pilot, remained inside the spacecraft during the extravehicular activity (EVA). Astronaut White died in the Apollo/Saturn 204 fire at Cape Kennedy on January 27, 1967. (Photo by NASA)

“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)

Mug shot of De Gracy (sic) and Edward Dalton. Details unknown. Central Police Station, Sydney, around 1920. (Photo by NSW Police Forensic Photography Archive, Justice & Police Museum, Histiric Houses Trust of NSW)

A man from the Dominican Republic wears a devil mask while dancing in the street during Carnival celebrations in Panama City, Monday, February 16, 2015. (Photo by Arnulfo Franco/AP Photo)

A performer takes part in the opening of the Temple Fair, part of Chinese New Year celebrations at Ditan Park, also known as the Temple of Earth, in Beijing, February 18, 2015. (Photo by Kim Kyung-Hoon/Reuters)

“Show us our butts! Mucawana tribe – Angola. In Soba village, the Muhacaona (Mucawana) tribe, perhaps the best place i have visited. They use cow dung and fat to make this so nice haircut, and love the beads. They asked me to make pictures of their backs... and butts to see on the camera screen if everything was perfect!”. (Photo and comments by Eric Lafforgue)

Partially demolished houses stand in the Vila Autodromo slum with the Rio 2016 Olympic Park in the background in Rio de Janeiro, Brazil, February 25, 2016. (Photo by Ricardo Moraes/Reuters)