An enthusiast dressed as a zombie takes part in the annual Zombie Walk festival in Prague June 1, 2013. (Photo by David W. Cerny/Reuters)

Replica of an old traditional Icelandic house from the 1800 with eruption of Iceland's Eyjafjallajökull volcano, 2013. (Photo by Ingólfur Bjargmundsson/Getty Images)

“In beard and hat”; Udine, Friuli-Venezia Giulia, Italy, 2013. (Photo by Giulio Magnifico)

Huge pack of starlings in the sky of the Negev, Israel, on January 21, 2013. Birds are turned in evening twilight before settling to sleep. (Photo by Eliyahu Hershkovitz)

A burning tank is in Daraa, on March 9, 2013. (Photo by Ali Abu-Salah/Reuters/Shaam News Network via The Atlantic)

Storm chaser Brad Mack from Buena Park California videotapes a rotating supercell storm west of Newcastle, Texas April 9, 2013. Many of the storms in Tornado Alley that were forecast to be severe this week were taken out by a cold front from Canada. Picture taken April 9, 2013. (Photo by Gene Blevins/Reuters)

View at one of the sculptures by Swiss artist H.R. Giger during the opening of the Ars Electronica 2013 exhibition “HR Giger. The Art of Biomechanics” in Linz, Austria, 04 September 2013. (Photo by EPA/RUBRA)

Kent Josephso organizes his 8mm tracer rounds during the Big Sandy Shoot in Mohave County, Arizona March 23, 2013. The Big Sandy Shoot is the largest organized machine gun shoot in the United States attended by shooters from around the country. Vintage and replica style machine guns and cannons are some of the weapons displayed during the event. Picture taken March 22, 2013. (Photo by Joshua Lott/Reuters)