A volcanic eruption at Mount Etna’s Vorgaine crater in Sicily, Italy on December 3, 2015. (Photo by Marco Restivo/Barcroft Media)

People walk past a man preaching along a train track in Ikeja district in Nigeria's commercial capital Lagos April 12, 2016. (Photo by Akintunde Akinleye/Reuters)

A seagull flies through a rainbow near the Savannah River and the open spillway at Thurmond Dam in Clarks Hill, SC, Monday, January 4, 2016. (Photo by Michael Holahan/Augusta Chronicle via AP Photo)

Children attend a war safety awareness class conducted by civil defence members, in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria May 14, 2016. (Photo by Khalil Ashawi/Reuters)

A general view of atmosphere at the annual VOLT Festival in Sopron, 208 kms west of Budapest, Hungary on August 16, 2016. (Photo by Mudra László/Rockstar Photographers)

A member of the Revolutionary Armed Forces of Colombia (FARC) pose for a picture at a camp in the Colombian mountains on February 2005. (Photo by Frank Piasecki Poulsen)

Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)

Kendall Jenner and Kylie Jenner seen in this celebrity social media picture on September 1, 2016. (Photo by XposurePhotos.com)