(From left) Strawberries and cream gelato; peanut butter ice cream sandwich; dirty mint chip. Brian Leatart/Courtesy of Houghton Mifflin Harcourt hide caption

itoggle caption Brian Leatart/Courtesy of Houghton Mifflin Harcourt

Thousands of students from around the world flock to courses near Bologna, in central Italy, at the headquarters of Carpigiani, the leading global manufacturer of gelato-making machines. Giuseppe Cacace/AFP/Getty Images hide caption

itoggle caption Giuseppe Cacace/AFP/Getty Images