Occupy movement marches, strikes and other acts of civil disobedience would \"disrupt the status quo\" of about 135 US cities Tuesday, movement organizers said. \"We call upon people to refrain from shopping, walk out of class, take the day off of work and other creative forms of resistance disrupting the status quo,\" organizers said in an e-mail Thursday. Key cities targeted for the \"general strike,\" or \"a day without the 99 percent\" -- which protest organizers said would be \"the first truly nationwide general strike in US history\" -- were New York, California\'s San Francisco-Oakland area and Los Angeles, Chicago and Seattle, the Occupy Wall Street Web site said. Marches were also planned for college towns such as Amherst, Mass., and Ann Arbor, Mich., the Web site said. Occupy-related groups called for strikes and demonstrations in more than 80 countries, in cities including Amsterdam, Athens, Barcelona, London, Melbourne, Rome, Seoul and Toronto, the Web site said. May 1 is already a date with strong historical significance in many countries, where it is a national holiday known as International Workers\' Day, celebrated by working people and labor unions. In the United States, May 1 is recognized as Law Day, to reflect on the role of law in the nation\'s foundation and to recognize its importance for society. New York Mayor Michael Bloomberg said his police department was prepared to manage what officials said would likely be a day of wide-ranging Occupy demonstrations, including possible bridge and tunnel blockades, dozens of small rallies and a \"pop-up occupation\" of Bryant Park, a privately managed public park across the street from Bank of America Corp.\'s 55-story tower. Protesters planned to march from Union Square to the city\'s Financial District. Officials in Seattle warned of the possibility of vandalism and violence, The Seattle Times reported. Other big actions planned for the West Coast included a march in the San Francisco Bay area. Organizers called off a plan to shut down the Golden Gate Bridge. In Los Angeles, protesters planned a \"4 Winds\" march and bike caravan to descend on the city\'s Financial District from all directions. Occupy organizers called specific attention to Chicago Tuesday -- and plan to focus on it afterward -- because the city is to host a summit of NATO countries\' heads of state and government May 20-21. The magazine Adbusters, which spearheaded the original Occupy Wall Street event, called Chicago \"the focal point of this global spiritual insurrection\" because of the summit.