Matt Galanti, 17, of Bothell, Wash., smokes marijuana from a glass bong at the opening day of the pro-marijuana rally Seattle Hempfest, Aug. 17, 2012, as friends Zach Casselman, 18, of Bothell, and Clay Graeber, 20, of Bothell, look on.
SEATTLE - AUGUST 16: Devon Phillips (R) and his daughter Ana Phillips (L) sells artificial marijuana leaf leis at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 16: Mack Bud, self-described as "marijuana man", sells artificial marijuana leaf leis at Hempfest in Seattle August 16, 2003. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 16: Seattle police take into custody a man suspected of selling marijuana at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
Hempfest 2011 in Seattle.
SEATTLE - AUGUST 21: An older woman smokes a marijuana joint at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Water pipes, used as bongs to smoke mariijuana are for sale at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: A young man smokes marijuana from a bong at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
Hempfest – the world’s largest pro-pot rally – returns to Seattle August 16-18. Take a look back at previous years here.
SEATTLE - AUGUST 16: Mike Volp sells artificial marijuana leaf leis and marijuana glasses at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Jordan LeRoy sports marijuana glasses and a marijuana lei at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Nani Wolf smokes a large marijuana cigarette at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: More than 150,000 people were expected to attend Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Participants at Hempfest gather under a makeshift tarp to escape the rain and smoke marijuana on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: People participate in Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Tori Taueu-Misa smokes a large marijuana joint at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
Police interrupted the second annual Tacoma Hempfest on Saturday, citing vendors for possessing marijuana-like paraphernalia despite having valid permits. (Associated Press)
A marijuana purveyor had hoped to build a two-pound joint during Hempfest.
SEATTLE - AUGUST 16: SEATTLE - AUGUST 16: A participant smokes a marijuana cigarette at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 16: Betsy Burbank shows off her homemade flag at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 16: Former police officers David Otto (L) and Walter Mckay (R) speak to participants at Hempfest August 16, 2003 in Seattle. Otto and Mckay belong to Law Enforcement Against Prohibition (LEAP) a group that advocates marijuana law reform. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 16: A participant smokes a marijuana cigarette at Hempfest August 16, 2003 in Seattle. Hempfest is the largest rally and festival advocating marijuana drug war reforms in the world and was expecting over 170,000 participants. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Anti-George Bush t-shirts for sale at Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)
SEATTLE - AUGUST 21: Jecca Classen tries to keep her mohawk from blowing in the wind while attending Hempfest on August 21, 2004 in Seattle, Washington. More than 150,000 people were expected to attend Hempfest at Seattle's Myrtle Edwards Park on Seattle's waterfront on August 21-22, 2004. The event is billed as the world's largest drug-policy reform rally. Events included political speakers and dozens of bands and performers on six stages and over 20 organizations were present registering new voters. (Photo by Ron Wurzer/Getty Images)