Feb. 15, 2003, Iraq War protest in Rome the largest antiwar rally in history

When it comes to protests, the book of Guinness World Records currently lists the Feb. 15, 2003, Iraq War protest in Rome as the largest antiwar rally in history. The event drew an estimated crowd of 3 million. On that same day, protesters gathered in nearly 600 cities in a coordinated global effort to express moral outrage against the U.S. invasion of Iraq. This included a reported 1.3 million protesters in Barcelona, Spain, and between 750,000 and 2 million protesters in London [sources: Guinness Book of World Records, BBC]. All told, between 6 and 10 million people participated in the global protest [source: BBC].