Critical Mass rides have been perceived as protest activities.

Critical Mass rides have generated considerable controversy and public opposition.

I attended the London Critical Mass ride last Friday to talk to the participants.

What are the different roles for the Ciclovia versus the Critical Mass ride?

Critical Mass rides vary greatly in many respects, including frequency and number of participants.

Some Critical Mass rides themselves have had incidents of full or partial nudity.

(news article, Nov. 4) as saying that the monthly Critical Mass ride was not "political."

Critical Mass rides began 12 years ago in San Francisco and have since spread to more than 300 cities around the world, organizers say.

The monthly Critical Mass ride draws thousands of participants in the summer months.

"We were very concerned with the city's extraordinary request for a preliminary injunction to enjoin the Critical Mass ride."