Denver Mayor Michael Hancock has put together a team at the city that will thoroughly review what went wrong at last week's 4/20 rally.

According to Denver Police Chief Roger White, Civic Center Park suffered because of a lack of security.

Several people barreled through gates to get in without being screened. And the morning after, the city woke up to a huge mess: a park that hadn't been properly cleaned up.

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Monday, the mayor called the media to the park to explain that the team will look closely at Denver's permitting process for large events.

He didn't get specific about what changes could be coming as the review, which includes several departments, has only just begun.

The mayor did say 4/20 event organizers could face penalties for some of last week's troubles.

His main concern was safety. He says he was bothered by the fact that people made their way into the event without being screened.

Hancock wouldn't say how next year's event might be different but acknowledged that the city will be taking a close look at the fact that the very nature of the marijuana event promotes illegal activity, that is, smoking pot in public.

"We always want to be mindful of the city not promoting lawlessness. And when I look out that office at the 4/20 event any year and I see the plume, that bothers me. Because at the end of the day the city must be seen as the guardians of the city, treasury and our treasured spaces. But also the law," Hancock said.

Mayor Hancock said while the 4/20 event is the reason for this review, any changes to the permitting process would be applied to all events.