It was hard to see the ground at Civic Center Park, Thursday, because of all the people there to get high at the 420 rally. This morning, it was hard to see the ground because of all the trash left over.

A lot of people complained about what they saw; some people even joined in the cleanup efforts.

"I saw some folks over here picking up trash and I thought, 'You know, I could pick up some, too,'" Molly Campbell said. "I think it's kind of a metaphor for the world. We all create the world and if we all do something to make it a little bit better, then it will be better."

There are still questions about who is responsible for the mess. Santino Walter, an organizer for the 420 rally, said no one who showed up to yesterday's event should get any of the blame.

"The people who attended the 420 rally did not do this," Walter said. "This is a result of 80 to a hundred trash bags being cut open and dumped."

He said about 16 people piled up all the trash until crews could pick it up this morning. However, he said when crews came to pick it up early this morning, every bag on the park had been cut open and dumped out.

"It's really unfair to the people who cleaned last night," he said.

A different coordinator, Miguel Lopez, said cleanup hit a snag last night when a man with a knife started cutting open trash bags. He said when the man was asked to leave, that person allegedly pulled a knife on cleanup crews. Denver Police said they responded to a disturbance call at the park around 10:45 p.m. but no complaint was filed.

A vendor who spoke with 9NEWS said he blames all the trash on a disorganized event. He said a guest told him event staff was telling people to leave their trash on the ground and crews would pick it up later. The vendor said he didn't see trash cans in the park until just before 3:30 Thursday afternoon.

According to the City of Denver, event organizers' permit doesn't expire until midnight. So, as long as trash is cleaned up by then, they won't face any penalties.

The city's Office of Special Events said a damage deposit of more than 2,800 dollars was paid prior to yesterday's rally. Officials said organizers will do a walkthrough with the city's Parks and Recreation staff to assess any damage. If they find any, the cost will be deducted from their deposit.