A woman waits to hear about her sister, a teacher, following a shooting at the Sandy Hook Elementary School in Newtown, Connecticut. A man killed his mother at their home and then opened fire inside the elementary school where she taught, massacring 26 people, including 20 children, as youngsters cowered in fear to the sound of gunshots reverberating through the building and screams echoing over the intercom. (Photo by Jessica Hill/Associated Press)

Smoke billows from Jinnah International Airport in Karachi, Pakistan, June 9, 2014. (Photo by Athar Hussain/Reuters)

A man takes a selfie next to a flooded street due to the overflowing of the Mapocho river during heavy rains in Santiago on April 17, 2016. Four million people in Santiago were without tap water Sunday after unusually heavy rain pounding central Chile triggered landslides that fouled the city's water supply and forced the closure of the world's biggest copper mine, officials said. (Photo by Martin Bernetti/AFP Photo)

A wildlife ranger strokes a northern white rhino, only three of its kind left in the world, ahead of the Giant Club Summit of African leaders and others on tackling poaching of elephants and rhinos, Ol Pejeta conservancy near the town of Nanyuki, Laikipia County, Kenya, April 28, 2016. (Photo by Siegfried Modola/Reuters)

A woman watches rescue operations after a bus and a truck crashed on the road that links the Honduran capital with the south of the country, near Germania, 11 km south of Tegucigalpa on February 5, 2017. At least 12 people were killed and 35 injured of some 70 who were on board the bus. (Photo by Orlando Sierra/AFP Photo)

A child dressed as a Roman centurion poses during a parade to mark the anniversary of the foundation of Rome in 753 BC, on April 23, 2017 in Rome. (Photo by Alberto Pizzoli/AFP Photo)

Models present Victoria Secret Fantasy Bras priced at $2 million each during a media preview of the Singapore JewelFest in Singapore October 8, 2015. The festival which is in its 13th year, sees over 42 Asian designers participating and over $300 million worth of jewels for sale. It opens from October 9 to 18. (Photo by Edgar Su/Reuters)

Evan Leversage, who is terminally ill with brain cancer, is greeted by a Christmas decorated dog with his mother Nicole Wellwood (L), and his father Travis Leversage (2nd R) in St. George, Ontario, Canada October 24, 2015. Evan Leversage is a seven-year-old boy who has been living with inoperable brain cancer since he was two years old. His family has organized a Christmas celebration in October complete with a full parade, in case Evan does not live to celebrate his last Christmas day on the traditional date of December 25, according to local media. (Photo by Mark Blinch/Reuters)