An Egyptian boy holds a camel at the Berqash camel market northeast of Cairo, on August 17, 2018. Muslims across the world are preparing for the Eid al-Adha holiday when custom requires the faithful to make a sacrifice. (Photo by Khaled Desouki/AFP Photo)

Dancers resting on the rooftop of the SKD Theatre Asakusa, Tokyo, 1949. (Photo by Tanuma Takeyoshi/The Guardian)

A young Sandinista guerrilla takes aim with his 45 pistol as he stands waiting to do combat with the Nicaraguan National Guard in Managua June 23, 1979. The guerrillas still occupy major parts of the Capitol City. (Photo by McLendon/AP Photo)

“Lobsang and 66 fellow monks were imprisoned in 1959. When released 21 years later, he was one of only three survivors. While in prison his best friend, a rinpoche, died in his arms. Tensin was later discovered to be the reincarnation of that friend. Lobsang said there are so many characteristics of his old friend in the young boy”. (Photo and caption by Phil Borges)

American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)

“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)