The O’Reilly Factor sent Jesse Watters to Denver, Colo., for the popular 4/20 celebration. The annual marijuana holiday coincided with Easter weekend this year and tens of thousands attended.

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By late afternoon, authorities had issued 47 citations for public marijuana consumption and made 16 arrests. Denver Health Medical Center paramedics treated 14 people, including three that were taken to detox.

Watters alerted revelers to a new study that found marijuana can damage your brain. Plus, he encountered several underage people in attendance, including some as young as 13 and 14.

Watch Watters' World above, and check out Tuesday's "Factor" at 8/11p ET as Charles Krauthammer weighs in on how Hillary Clinton could be defeated in 2016.

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