The city, which has a population of about 650,000, has more than 60 marijuana outlets, which sell different hybrids of the drug as well as cookies, creams, pipes and T-shirts. Just a decade ago, it was illegal to sell alcohol on a Sunday but now anyone 21 years or older is allowed to purchase marijuana.
As more tourists are drawn to experience the city's marijuana culture, thousands of jobs have been created, including a cannabis critic for the local paper.
Police officers were worried when Amendment 64 first passed, a Denver police officer tells Sherren, but that fear turned out to be unfounded.
"We found there hasn't been much of a change of anything," he said. "Basically, officers aren't seeing much of a change in how they do police work."
But not all lawmakers are convinced legalization is the right route. Gov. John Hickenlooper recently called legalization reckless, while Denver Mayor Michael B. Hancock said he's against legalization.
Despite their concerns, the state has collected some $60 million US in pot tax revenue since passing the amendment. Last month, Hancock spent $4 million on new programs for the city.
But because legalization remains illegal on the federal level, most major banks are reluctant to handle the money marijuana dispensaries bring in and businesses are unable to use credit or debit cards.
The manager of 3D Cannabis centre says being robbed is his biggest fear and he worries about it daily.
Watch Sherren's full report by clicking on the video above.