For the second year in a row, University of Colorado-Boulder officials shut down the campus in an effort to end the annual April 20 afternoon smoke-out. 

With no place to celebrate 4/20 in Boulder, some CU-Boulder students and former Boulder 4/20 revelers flocked to Denver's Civic Center Park, where a crowd of several thousand turned out for concerts, speakers and the collective 4:20 p.m. light-up on Saturday.  

CU freshman Ian Maclin traveled to Denver with a group of students because CU-Boulder officials closed campus. 

Maclin said he understands why officials don't want crowds of pot-smokers on campus, but added that it would have been “really convenient” to stay in Boulder. 

“Nobody's really hurting anyone and that's their whole reasoning behind it,” Maclin said early in the afternoon. “(It) doesn't make sense.” 

Colorado citizens voted in November to legalize recreational marijuana for people 21 and older. Though smoking marijuana in public is still illegal, Denver police officials said they would not focus on ticketing participants at the Denver 4/20 rally. Rather, police kept watch at Civic Center Park, standing in groups and monitoring the event for any suspicious behavior after Monday's Boston Marathon bombings.

As a university library employee, 19-year-old CU freshman Jon Ho said he saw firsthand how campus officials in Boulder had “beefed up” security in advance of 4/20. 

He said he saw squad cars in front of the library and all over campus before he traveled to Denver to celebrate. 

“It's a little excessive,” he said. “Campus shutting down -- I'm fine with that, but what they're doing is preventative measures. Putting squad cars in front of every dorm. It's a little excessive in that sense. Closing off campus I understand because it brings a lot of unwanted people into the city and into the university.”

The crowd of thousands in Denver sat or stood peacefully, smoking, eating and listening to various performers and speakers at Civic Center Park on Saturday afternoon. In the back of CU freshman Conner Stoesser's mind was the possibility that another bombing, like the one at the finish line of the Boston Marathon, could take place in Denver, he said. 

With such a huge crowd, Denver's 4/20 rally would be an easy target, but Stoesser said he wasn't “very concerned.” 

“There's always a chance,” he said. “You can't live life being afraid.” 

Stoesser said the first link that popped up when he Googled CU in high school was one about the campus' celebration of 4/20. He didn't go to CU just to smoke weed, he said, but it would've been fun to be part of the Boulder 4/20 tradition. 

Stoesser wondered why CU officials didn't try to regulate the 4/20 gathering on campus rather than shut it down completely. 

“All that business could be really good for the Hill,” he said. “Just the principle of the festival. Everybody's there to chill out, nobody's getting hurt. It's very under control. If the campus decided to regulate it, I think it could actually be really beneficial for the school and a lot of the businesses on the Hill.”

Noelani Martinez and Allison Fowler, both from near Pueblo, Colo., brought six multi-colored hula hoops to Civic Center Park to share. They used to celebrate 4/20 in Boulder, they said. 

“If they want to give this awesome festival to Denver . . .” Martinez said. “Embrace what you're known for. There's no reason to try to hide it. We are who we are. If we like to feel good, there should be no problem with that.” 

Fowler said CU shutting down its 4/20 party has been both good and bad. She said she always had a good time celebrating 4/20 in Boulder, but now she gets to party with thousands of people in front of the Capitol building in Denver. 

“(Boulder) was a really fun festival, but now there's all these people here, something like 30,000 from out of state,” said Fowler, sporting neon green fishnet arm gauntlets. “That's insanity. I like this one in the park. I had fun here last year. Last year was a blast.”