Across the world, marijuana enthusiasts are celebrating the unofficial holiday known as 4/20. Because marijuana laws vary from country to country, however, celebrating can take a multitude of forms — from smoking a joint in your private residence to lighting up in front of a government building to protest prohibition.

Here's how people are celebrating 4/20 across the world.

1. Denver, Colorado: Medical and recreational marijuana legal.

2. Ottawa, Canada: Medical marijuana legal.

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3. Hong Kong, China: Marijuana illegal. 

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4. Melbourne, Australia: Medical marijuana legal.

5. San Francisco, California ("Hippie Hill"): Medical marijuana legal.

6. Arlington, Virginia (The Pentagon): Medical marijuana legal.

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7. Greece: Marijuana illegal. 

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8. London, England (Hyde Park): Marijuana illegal.

9. Toronto, Canada: Medical marijuana legal. 

10. Rio de Janeiro, Brazil: Marijuana illegal. 

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Check out part one of ATTN:'s video series on the medical marijuana refugee movement.

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