It began as the brainchild of activists across the border in Canada when an anti-consumerism magazine put out a call in July for supporters to occupy Wall Street. Now, three weeks after a few hundred people heeded that initial call and rolled out their sleeping bags in a park in New York's financial district, they are being joined by supporters in cities across the US and beyond. Protesters against corporate greed, unemployment and the political corruption that they say Wall Street represents have taken to the streets in Boston, Los Angeles, St Louis and Kansas City. The core group, Occupy Wall Street, claims people will take part in demonstrations in as many as 147 US cities this month, while the website occupytogether.org lists 47 US states as being involved. Around the world, protests in Canada, the UK, Germany and Sweden are also planned, they say. The speed of the leaderless movement's growth has taken many by surprise. The movement, which organisers say has its roots in the Arab spring and in Madrid's Puerta del Sol protests, has been galvanised by recent media attention. Last week, the Guardian reported that a NYPD police officer had been filmed spraying four women protesters with pepper spray. On Saturday, a peaceful march on Brooklyn bridge intended as a call to the other four boroughs of New York to join in resulted in 700 arrests. Some protesters claim the police trapped them.