A boy holds his mother's leg as he cries in front of their damaged house after a strong 6.6 magnitude earthquake at Longmen village, Lushan county in Ya'an, Sichuan province. (Photo by Jason Lee/Reuters)

Residents observe a police officer take up position during an operation at the Mare slums complex in Rio de Janeiro March 25, 2014. The federal troops have taken control of security operations in Mare slums complex to help quell a surge in violent crime following attacks by drug traffickers on police posts in three slums on the north side of the city, government officials said. (Photo by Ricardo Moraes/Reuters)

“Only the most intrepid urban explorers cross the tattered ruins of the old Iron Curtain to endure the excessive bureaucracy, military paranoia and freezing winds of the East to hunt for the ghosts of an empire. Rebecca Litchfield is one who couldn't resist the haunting allure of the ruins of the Soviet Union”. – Yahoo News. Photo: Hungary, MAV 424 Steam Train. (Photo by Rebecca Bathory)

People in costume take photos during a Halloween event on October 31, 2015 in Lan Kwai Fong, Central District, Hong Kong. Halloween, a named taken from 'All Hallows' Even' falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Jerome Favre/Getty Images)

Photographer Andy Hall joins the thousands of fans from west Africa who have gathered for Baaba Maal's annual Blues du Fleuve festival in Senegal. Here: Dancers wait to perform on stage. (Photo by Andy Hall/The Observer)

Indian Hindu devotees wait to take part in an event to mark Pongal in Mumbai on January 15, 2016. Pongal, which coincides with the Hindu festival Makara Sankranthi, is a thanksgiving and harvest celebrated throughout India and specifically by those from the Indian state of Tamil Nadu. (Photo by Indranil Mukherjee/AFP Photo)

A worker puts the final touches to a replica of a Beijing opera mask made with lemons and oranges during the 82th Lemon festival in Menton February 12, 2015. Over 20,000 hours work for teams to set up the festival and some 145 metric tons of lemons and oranges are used to make displays during the 82th festival, which is themed “Tribulations of a lemon in China”, and runs from February 14 through March 4. (Photo by Eric Gaillard/Reuters)