DENVER

- 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 explained, 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 said, as the scent of marijuana competes with the smell of sawdust and wet paint in the cavernous store.

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?

Throughout 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," recalled 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."

For now, all the focus is on 2014. This being Colorado, there will be more than a few joints lit up on New Year's Eve. Pot fans plan to don 1920s-era attire for a "Prohibition Is Over!" party and take turns using concentrated pot inside the "dab bus."

Williams says he's done everything he can, including hiring seven additional staffers to handle customers.

"Are we ready to go? Yes," he said. "What's going to happen? I don't know."