Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)
Participants wear traditional clogs as shepherds lead their sheep through the center of Madrid, October 28, 2012. (Photo by Andres Kudacki/Associated Press)
LOS ANGELES - OCTOBER 31: Mike Tyson poses at the Halloween Mansion Party hosted by Haylie Duff on October 31, 2005 in Hollywood, Los Angeles, California. (Photo by David Livingston/Getty Images)
A portrait of Kazakh historical figure Ablai Khan is projected on a building in downtown Astana, Kazakhstan, October 8, 2015. (Photo by Shamil Zhumatov/Reuters)
Students play in their school yard on the first day of the new school term at a primary school in Baghdad, October 18, 2015. (Photo by Ahmed Saad/Reuters)