DENVER - The world's first state-licensed marijuana retailers legally permitted to sell pot for recreational use opened for business in Colorado on Wednesday with long lines of customers, marking a new chapter in America's drug culture.

Roughly three dozen former medical marijuana dispensaries newly cleared by state regulators to sell pot to consumers interested in nothing more than its mind- and mood-altering properties began welcoming customers as early as 8 am MST (1500 GMT).

Hundreds of patrons, some from distant states and many huddling outside in the bitter cold and snow for hours, cued up to be among the first buyers.

"This is an historic moment," Jacob Elliott, 31, a defense contractor from Leesburg, Virginia, near Washington, D.C., said in line outside the 3D Cannabis Center in Denver. "I never thought it would happen."

The highly-anticipated New Year's Day opening launched an unprecedented commercial cannabis market that Colorado officials expect will ultimately gross $578 million in annual revenues, including $67 million in tax receipts for the state.

Possession, cultivation and private personal consumption of marijuana by adults for the sake of just getting high has already been legal in Colorado for more than a year under a state constitutional amendment approved by voters.

As of Wednesday, however, cannabis was being legally produced, sold and taxed in a system modeled after a regime many states have in place for alcohol sales - but which exists for marijuana nowhere in the world outside of Colorado.

Even in the Netherlands, where some coffee shops and nightclubs are widely known to sell cannabis products with the informal consent of authorities, back-end distribution of the drug to those businesses remains illegal.

Customer No. 1 at Botana Care in the Denver suburb of Northglenn was Jesse Phillips, 32, an assembly-line worker who had camped outside the shop since 1 am.