Rachel Schaefer of Denver smokes marijuana on the official opening night of Club 64, a marijuana-specific social club, where a New Year's Eve party was held, in Denver, Monday Dec. 31, 2012. (AP Photo/Brennan Linsley)

The Impact Of Smoking Marijuana Regularly On Your Lungs, According To Science

Why is marijuana still classified as a dangerous drug when study after study shows it to be safer than tobacco?