Denver is ramping up security for Saturday's 4/20 celebration. But police are less concerned about the thick cloud of marijuana smoke that will floating above the mile high city Saturday afternoon and more focused on protecting the massive crowd of happy pot smokers in the wake of this week's deadly Boston Marathon attacks. 4/20 organizers are expecting up to 80,000 people to attend this year's event, as it is the first celebration since Colorado voted to legalize recreational marijuana use.
