Beginning in 2002, and continuing after the 2003 invasion of Iraq, large-scale protests against the Iraq War were held in many cities worldwide, often coordinated to occur simultaneously around the world.
There were protests in England, Italy, France, and the United States, and many others countries. In 2004 Guinness listed as the largest protest in human history. Many Americans thought this war was a mistake. In Rome, there was a 3 million people protest that Guinness called the biggest anti-war protest in human history.
These demonstrations against the war were mainly organized by anti-war organizations, many of whom had been formed in opposition to the invasion of Afghanistan. It was estimated that around 36 million people participated in protests worldwide.