Patrick Scolaro and Cory Sullivan of Boca Raton playfully duke it out wearing masks that were handed out to attendees of the Rock the Vote concert at Mizner Park after the debate. (Photo by Allen Eyestone/The Palm Beach Post)

A man dressed as a zombie poses during the Thrill The World 2009 event, which sees fans from all over the world dance simultaneous to Michael Jackson's “Thriller” at Luna Park on October 25, 2009 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

This photo provided by NASA shows a full moon rising behind the United Launch Alliance Atlas V rocket with NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft onboard at the Cape Canaveral Air Force Station Space Launch Complex 41, Sunday, November 17, 2013, Cape Canaveral, Florida. NASA's next Mars-bound spacecraft, the Mars Atmosphere and Volatile Evolution, or MAVEN, is the first spacecraft devoted to exploring and understanding the Martian upper atmosphere. (Photo by Bill Ingalls/AP Photo/NASA)

Life as tenant farmers in Kasungu, northern Malawi, can be a struggle for families trapped in poverty, who feel forced to rely on their children’s help, impacting schooling. Here: A tobacco field at a farm in Kasungu region, Malawi. Tobacco is the country’s most important export crop, with tobacco leaf from Malawi filling cigarettes found all over the world. Here: Tiyamike Phiri hopes to become a nurse because she wants to travel the country and help others. (Photo by David Levene/The Guardian)

“There Were Early Indications that Maxine was Not a Good Fit for the Surgical Team”. (Photo by Studio d'Xavier)

Three secondary schoolboys smoking an illicit cigarette in Hyde Park, London. (Photo by Evening Standard/Getty Images). May 1972

Participants dressed as Santa Claus take part in the Great Edinburgh Santa Run on December 11, 2011 in Edinburgh, Scotland. Around a thousand people took part in the annual fundraising event, with all money raised being donated to the charity “When You Wish Upon a Star”. (Photo by Jeff J. Mitchell/Getty Images)