A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

Cuban Daymara A., 20, poses for a photograph after she crossed the border from Colombia through the jungle into La Miel, in the province of Guna Yala, Panama December 2, 2015. According to local authorities in La Miel, some 100 to 150 Cubans have been entering Panama from Colombia every day for the last three months. Scores of Cubans have come to Panama as they seek overland passage towards the United States fearing a recent detente between Washington and Havana could end their preferential treatment. (Photo by Carlos Jasso/Reuters)

Photographer Tyler Shields had become comfortable, a feeling he found “terrible” as an artist. He wanted to do something challenging, something that pushed the human boundaries. So he spent a year documenting heights, fear, energy and falling – a series he calls “Suspense”. Photo: “Balloon”. (Photo by Tyler Shields)

Krista Long began snapping pics of people sliding down a water slide after many visits to the local water park with her tween daughters. The result is an action-packed series that show emotions ranging, she says, “from pure joy to fear, in anticipation of the inevitable splash-down!” (Photo by Krista Long)

"Mustang Wanted" – is it so itself calls. It seems, he is 26 years old. It seems, it from Kiev, Ukraine. That I can tell still... Fearless man. (Photo by Mustang Wanted)

Gliding past the planet Jupiter, the Cassini spacecraft captures this awe inspiring view of active Io, Jupiter's third largest satellite, with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet's relative size, April 20, 2001. The Cassini spacecraft itself was about 10 million kilometers from Jupiter when recording the image data. (Photo courtesy of NASA/Newsmakers)

Standard Rose 'Osiria' distinguishes itself from other roses due to its nicely-shaped and attractive flowers. This well-known fragrant floribunda rose is now available as a colourful standard. This very striking rose has an unusual colour combination. The petals are flaming red on the inside and white on the outside.

A man takes a photo as a puff of smoke comes from Mount Agung volcano, taken from the Rendang sub-district in Karangasem Regency on Indonesia's resort island of Bali on November 23, 2017. Thousands living in the shadow of the rumbling volcano on Indonesia's resort island of Bali fled on November 22 as fears grow that it could erupt for the first time in more than 50 years. (Photo by Sonny Tumbelaka/AFP Photo)