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Brian Vicente co-director of the Yes on 64 campaign waits to start a news conference about the legalization of marijuana at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

Brian Vicente co-director of the Yes on 64 campaign waits to start a news conference about the legalization of marijuana at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

The marijuana debate

Pot smokers formally gained the right to light up in Colorado on Dec. 10 as Governor John Hickenlooper

signed into effect a controversial ballot measure legalizing marijuana

for adult recreational use in what proponents hailed as a "historic

day."