A marijuana plant is displayed during the 2016 Cannabis Business Summit & Expo last month in Oakland, Calif. Justin Sullivan/Getty Images hide caption
recreational marijuana
Wednesday
Kurt Britz checks a driver's license at the 3-D Denver Discrete Dispensary on Jan. 1, 2014, the first day recreational marijuana sales were legal in Colorado. Possession remains illegal for those under 21 years old, and statistics show a widening racial gap in arrests for those offenses. Theo Stroomer/Getty Images hide caption
As Adults Legally Smoke Pot In Colorado, More Minority Kids Arrested For It
Monday
Wednesday
A budtender prepares an edible sale for a customer at LivWell Broadway in Denver. Craig F. Walker/Denver Post via Getty Images hide caption
Monday
Two men inspect the goods at at Farma, a marijuana dispensary in Portland, Oregon. The state's first week of retail sales brought in an estimated $11 million, a trade group says. Josh Edelson/AFP/Getty Images hide caption
Monday
Friday
Partygoers attend a Prohibition-era themed New Year's Eve party celebrating the start of retail pot sales, at a bar in Denver on Dec. 31, 2013. Brennan Linsley/AP hide caption
Awesome Tips, Dude: Denver May Allow Pot In Bars, Restaurants
Wednesday
In Oregon, people can grow up to four marijuana plants per household. Elaine Thompson/AP hide caption
Wednesday
Grand Daddy Purple, Skunk #1, Sugar Daddy Courtesy of Chronicle Books hide caption
Tuesday
Tuesday
Deuel County Sheriff Adam Hayward shows off a container of confiscated marijuana in Chappell, Neb., in July. Nikki Kahn/The Washington Post/Getty Images hide caption
Nebraska Says Colorado Pot Isn't Staying Across The Border
Friday
Officials in Aspen have put out a brochure on how to use marijuana safely and legally. Marci Krivonen hide caption
Getting High Safely: Aspen Launches Marijuana Education Campaign
Thursday
Trimmers prepare the marijuana flower, or bud, to make it more appealing to consumers. They use scissors to snip off the leaves and stems. Brett Myers/Youth Radio hide caption
With Harvest Season, 'Trimmigrants' Flock To California's Pot Capital
Tuesday
Brooke Gehring, CEO of Patients Choice and Live Green Cannabis, stands in one of her company's grow houses in Denver. Kirk Siegler/NPR hide caption
Wednesday
Does smoking pot make it less likely that you'll go to college? iStockphoto hide caption