An artwork entitled “Are you still mad at me?” by John Isaacs is displayed at the Death: A Self-portrait exhibition at the Wellcome Collection on November 14, 2012 in London, England. The exhibition showcases 300 works from a unique collection by Richard Harris, a former antique print dealer from Chicago, devoted to the iconography of death. The display highlights art works, historical artifacts, anatomical illustrations and ephemera from around the world and opens on November 15, 2012 until February 24, 2013. (Photo by Peter Macdiarmid)

A man, right, throws a chair at a business window as another man tries to restrain a woman attempting to stop the damage, after march to City Hall for Freddie Gray, Saturday, April 25, 2015 in Baltimore. Gray died from spinal injuries about a week after he was arrested and transported in a police van. (Photo by Alex Brandon/AP Photo)

Police dog handlers wait outside the Loftus Road stadium after FA Cup Fourth Round between Queens Park Rangers and Chelsea on January 28, 2012 in London, England. Security has been stepped up after QPR player Anton Ferdinand recieved a package containing a bullet. (Photo by Dan Kitwood/Getty Images)

A South Korean military vehicle drives past barricades at the military check point, near the Demilitarized zone (DMZ) separating South and North Korea on December 20, 2011 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

A dog surfs at the 6th Annual Surf City surf dog contest in Huntington Beach, California September 28, 2014. (Photo by Lucy Nicholson/Reuters)

A dog rides a wave while competing during the 5th Annual Surf Dog competition at Huntington Beach, California, on September 29, 2013. (Photo by Frederic J. Brown/AFP Photo)

A dog rides a wave during the Surf City Surf Dog competition in Huntington Beach, California, U.S., September 25, 2016. The dogs compete in contest categories ranging from small to extra large, to two dogs on a board, as well as owner and dog. (Photo by Lucy Nicholson/Reuters)