With just one month to go until the Democratic National Convention in Denver, the city and the Secret Service are preparing for activist crowds estimated to be between 20,000 and 50,000.

Authorities are taking every precaution to make sure those looking to disrupt what the Democratic Party expects to be a historic moment don't go too far.

"I think we have to give the police the ability to act in certain circumstances where the intent ... is clear. That is to act before something actually happens," said Al Lacabe, safety manager in Denver.

Police will not comment on whether they will use stun prods and shields, or guns that fire pepper balls.

But at a recent City Council meeting, Denver police revealed some of the equipment they are acquiring to meet potential threats. On the list is something called "the bearcat," a tactical vehicle used by SWAT teams.

They'll also use mountain bikes to get around the convention scene more easily.

Police deny rumors they will be using any high-tech sonic wave weapons that cause people to lose control of their bowels, or that use "slime" or "goo" to immobilize protesters.

Meanwhile, protest groups say the city is overreacting.

"They are doing their best to make people afraid of us, to make people afraid to be anywhere near us," said Mark Cohen, of the group Recreate '68.

Though the group's name suggests it is interested in recreating the riots outside the 1968 Democratic convention in Chicago, the Recreate '68 Web site promises "peaceful, nonviolent protests" against the two-party system and says the name merely refers to the "spirit of mass political participation of the ‘60s."

The list of groups that have filed for permits spans the political spectrum. Aside from Recreate '68, another plans a massive immigrants' rights march. There will also be a demonstration against abortion.

The host party says it supports the free speech rights of those planning to demonstrate. But city officials hope the messages are delivered peacefully.

Convention CEO Leah Daughtry said they want "to ensure that those who come with messages have an opportunity and the space to bring their messages to the delegates."

FOX News' Alicia Acuna contributed to this report.