In this July 25, 2015 photo, youth eat a cooked pig's head as they wait for the start of carnival in Santiago, Cuba. (Photo by Ramon Espinosa/AP Photo)

Men cover their heads from the sun while riding on a motorcycle during a hot day in Cairo, Egypt, August 17, 2015. A heatwave killed at least 61 people across Egypt from Sunday to Tuesday and caused nearly 600 people to be admitted to hospital, Egypt's health ministry said on state news agency MENA on Wednesday. (Photo by Amr Abdallah Dalsh/Reuters)

A mahout rides on an elephant in the city of Amritsar, India, 08 November 2015. Such elephants are often accompanied by their caretakers who ask for alms from people in the streets. (Photo by Raminder Pal Singh/EPA)

Labourers unload gravel from a boat docked in Dala township, opposite Yangon city, Myanmar, November 12, 2015. (Photo by Olivia Harris/Reuters)

From the rocks of Arnhem Land to the backyards of the Sydney suburbs, from stretching by the pool to waiting for evening prayer, snapshots for the 2015 Australian Life prize demonstrated a nation in colour and motion. Here: Children Cooling Off at Dhiari Homeland. Local children get wet and cool in Arnhem Land. (Photo by Matthew Abbott/Australian Life Prize 2015)

Afghan women and a boy make their way in Kabul, Afghanistan, Sunday, November 15, 2015. (Photo by Rahmat Gul/AP Photo)

A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

A man rides his loaded tricycle next to three schoolgirls in Shanghai on December 11, 2015. (Photo by Johannes Eisele/AFP Photo)