Crash Course (sometimes stylized as CrashCourse) is an educational YouTube channel started by the Green brothers, Hank Green and John Green, who are notable for their VlogBrothers channel. Originally, John and Hank presented humanities and science courses to viewers, respectively, although the series has since expanded to incorporate courses by additional hosts.Crash Course was one of the 100 initial channels of YouTube's $100 million original channel initiative.