On Thursday, folks across the country are being asked to put their cigarettes out. Thursday marks the American Cancer Society's 36th annual Great American Smokeout. It's meant to encourage smokers to make a plan to quit. Dr. Richard Hurt is a Professor of Medicine at Mayo Clinic and the Director of Mayo's Nicotine Dependence Center. He said it's a positive way to encourage folks to kick the habit. "The Great American Smokeout really is a great way to focus attention on the single most preventable cause of death and disability in our country, and that is cigarette smoke," said Hurt.