The anti-Wall Street protest in Lower Manhattan entered its third week with hundreds of arrests after the group blocked traffic Saturday on the Brooklyn Bridge, and budding copycat movements across the U.S. continued to stage smaller-scale protests, planning them online on social networking sites.

Protesters held sizable gatherings in Chicago and Los Angeles. In other cities, like San Francisco and Pittsburgh, protests were smaller or existed only in a planning stage. A website,, lists groups that are offshoots of the New York protest. Activists have begun organizing outside the U.S., including in Prague, Melbourne and Montreal.

In New York, the protesters initially set out to occupy Wall Street but were rebuffed by police. Instead, the group set up in a nearby park, keeping the “Occupy Wall Street” moniker. The spread to other cities appears largely organic—the protests don’t have a central organizer—and the idea came from a Canadian magazine and grew on social media websites