A woman rolls a marijuana cigarette during the first “Expo Cannabis” fair in Montevideo December 14, 2014. Expo Cannabis offers conferences about different topics such as the medicinal use of cannabis and cultivation techniques as well as displaying hemp goods, cannabis cultivation items and seeds. (Photo by Andres Stapff/Reuters)

Cannabis seeds are displayed during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

People look at cannabis plants during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

Cannabis seeds are displayed during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

A man takes pictures of a cannabis plant displayed during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

A man takes pictures of a cannabis plant displayed during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

People look at cannabis plants during the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

A cannabis plant is displayed at the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)

People walk along the first “Expo Cannabis” fair in Montevideo December 14, 2014. (Photo by Andres Stapff/Reuters)