Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

Kazakh troops march during a parade of the armed forces to mark the Defender of the Fatherland Day in Astana, May 7, 2014. (Photo by Mukhtar Kholdorbekov/Reuters)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

These heart-warming photograph show an incredible bond between a wild lioness and the men fighting to save her species. The picture show Sirga – a 110lb lioness – and her adopted pride Valentin Gruener (not pictured) and Mikkel Legarth. Incredibly she treats the two men just like she would other lions and with their help she can now hunt for prey on her own. As a cub she was driven out from a pride and rescued by German and Danish duo Valentin and Mikkel who could not stand by and watch her die. She is now a beacon for hoped success of the Modisa Wildlife Project, founded in Botswana, Africa, by Valentin and Mikkel with the hope of saving the lion population. (Photo by Caters News)

People walk near a collapsed mosque following an earthquake in Meuredu, Pidie Jaya in the northern province of Aceh, Indonesia December 7, 2016. (Photo by Irwansyah Putra/Reuters/Antara Foto)

Barrier tape is tied around 15-month-old Shivani's ankle to prevent her from running away, while her mother Sarta Kalara works at a construction site nearby, in Ahmedabad, India, April 19, 2016. Kalara says she has no option but to tether her daughter Shivani to a stone despite her crying, while she and her husband work for 250 rupees ($3.8) each a shift digging holes for electricity cables in the city of Ahmedabad. There are about 40 million construction workers in India, at least one in five of them women, and the majority poor migrants who shift from site to site, building infrastructure for India's booming cities. Across the country it is not uncommon to see young children rolling in the sand and mud as their parents carry bricks or dig for new roads or luxury houses. (Photo by Amit Dave/Reuters)

A woman wearing a scarf to cover her face looks on as she waits for a passenger bus on a smoggy morning in New Delhi, India, November 8, 2017. The Great Smog of Delhi is an ongoing severe air-pollution event in New Delhi and adjoining areas in the National Capital Territory of India, in November 2017. Air pollution at this time peaked on both PM 2.5 and PM 10 levels. It has been reported as one of the worst levels of air quality in Delhi since 1999. (Photo by Saumya Khandelwal/Reuters)

A supporter of the presidential candidate for the Honduran Opposition Alliance Against the Dictatorship for the past election, Salvador Nasralla, lies on the street in front of police officers during a demonstration against the contested re-election of President Juan Orlando Hernandez, in Tegucigalpa, Honduras on January 21, 2018. (Photo by Orlando Sierra/AFP Photo)