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)

The Disney Fantasy cruise ship is docked for its christening on March 1, 2012 in New York City. (Photo by Jamie McCarthy/Getty Images)

Passengers climb to board an overcrowded train at a railway station in Dhaka August 8, 2013. Millions of residents in Dhaka are travelling home from the capital city to celebrate the Muslim Eid al-Fitr holiday, which marks the end of the Muslim holy fasting month of Ramadan. (Photo by Andrew Biraj/Reuters)

A man dressed as “El Chapulin Colorado”, a character by screenwriter Roberto Gomez Bolanos, performs for fans and media as they wait for the arrival of the funeral van carrying the body of Bolanos, at Mexican media company Televisa in Mexico City November 29, 2014. Mexican actor and screenwriter Roberto Gomez Bolanos, one of Latin America's most beloved comedians, whose slapstick acts charmed fans from Spain to Argentina for over four decades, died on Friday at the age 85. Known as “Chespirito”, a word play on “Little Shakespeare” for his diminutive stature and his prolific scripts, Gomez Bolanos created some of the region's most enduring comic characters. (Photo by Carlos Jasso/Reuters)

Young Buddhist novice monks play at a Tibetan nomadic summer grazing area on July 24, 2015 on the Tibetan Plateau in Yushu County, Qinghai, China. Tibetan nomads face many challenges to their traditional way of life including political pressures, forced resettlement by China's government, climate change and rapid modernization. The Tibetan Plateau, often called “The Roof of the World”, is the world's highest and largest plateau. (Photo by Kevin Frayer/Getty Images)

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