Legal Pot Sales Begin Amid Uncertainty in Colo. A gleaming white Apple store of weed is how Andy Williams sees his new Denver marijuana dispensary. Two floors of pot-growing rooms will have windows showing the shopping public how the mind-altering plant is grown. Shoppers will be able to peruse drying marijuana buds and see pot trimmers at work separating the valuable flowers from the less-prized stems and leaves. "It's going to be all white and beautiful," the 45-year-old ex-industrial engineer explains, excitedly gesturing around what just a few weeks ago was an empty warehouse space that will eventually house 40,000 square feet of cannabis strains. As Colorado prepares to be the first in the nation to allow recreational pot sales, opening Jan. 1, hopeful retailers like Williams are investing their fortunes into the legal recreational pot world - all for a chance to build even bigger ones in a fledgling industry that faces an uncertain future. Officials in Colorado and Washington, the other state where recreational pot goes on sale in mid-2014, as well as activists, policymakers and governments from around the U.S. and across the world will not be the only ones watching the experiment unfold. So too will the U.S. Department of Justice, which for now is not fighting to shut down the industries. "We are building an impressive showcase for the world, to show them this is an industry," Williams says, as the scent of marijuana competes with the smell of sawdust and wet paint in the cavernous store where he hopes to sell pot just like a bottle of wine. Will it be a showcase for a safe, regulated pot industry that generates hundreds of millions of dollars each year and saves money on locking up drug criminals, or one that will prove, once and for all, that the federal government has been right to ban pot since 1937? Cannabis was grown legally in the U.S. for centuries, even by George Washington. After Prohibition's end in the 1930s, federal authorities turned their sights on pot. The 1936 propaganda film "Reefer Madness" warned the public about a plant capable of turning people into mindless criminals. Over the years, pot activists and state governments managed to chip away at the ban, their first big victory coming in 1996 when California allowed medical marijuana. Today, 19 other states, including Colorado and Washington, and the District of Columbia have similar laws. Those in the business were nervous, fearing that federal agents would raid their shops. "It was scary," recalls Williams, who along with his brother borrowed some $630,000 from parents and relatives to open Medicine Man in 2009. I literally had dreams multiple times a week where I was in prison and couldn't see my wife or my child. Lot of sleepless nights. That same year, the Justice Department told federal prosecutors they should not focus investigative resources on patients and caregivers complying with state medical marijuana laws - but the department reserved the right to step in if there was abuse. In Colorado, the industry took off. Shops advertised on billboards and radio. Pot-growing warehouses along Interstate 70 in Denver grew so big that motorists started calling one stretch the "Green Zone" for its frequent skunky odor of pot. The city at one point had more marijuana dispensaries than Starbucks coffee shops, with some neighborhoods crowded with dispensary sign-wavers and banners offering free joints for new customers. Local officials have since ratcheted back such in-your-face ads.