SAN FRANCISCO (KGO) -- San Francisco's celebration of all things Canibus is history Thursday and many are giving this year's massive 4/20 gathering a thumbs up. There were no arrests at the event.
RELATED: Thousands gather for 4/20 at San Francisco's Golden Gate Park
The pot smoke of 15,000 joints and pipes almost created its own hazy fog bank on Hippie Hill.
"I like a good positive vibe, lovely ladies," said marijuana fan Olu Afolabi. "I came for a good time mostly."
Dozens of city park and rec workers began the massive garbage pickup in Golden Gate Park following the popular 4/20 celebration.
"You're supposed to take one piece of trash with you," said visitor Victor castro.
There were new rules at the celebration this year. The city issued a permit so you had to be 21 to get in. And there was no selling marijuana inside.
Local merchants paid for fencing, porta potties, and security.
When asked if she wanted to see more rules, attendee Jessica Daniels said, "It is what it is. People still came out and had a good time."
Last year, city workers collected a whopping 11 tons of trash left behind. This year, they picked up all day long. Most of the garbage will be recycled or composted.
PHOTOS: 15,000 people gather for Golden Gate Park 4/20 celebration
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San Francisco's 4/20 celebration runs smoothly with no arrests