In May of 1989 urban workers burst suddenly onto the Chinese political scene. They marched by the tens of thousands in huge Beijing street demonstrations, in delegations from hundreds of workplacesacts repeated on a smaller scale in cities throughout the country. While organized strikes were rare, small groups of dissident workers formed dozens of independent unions and other political groups from Sichuan to Shanghai, and from Inner Mongolia to Guangdong. The most visible, the Beijing Workers' Autonomous Union, set up in mid-April, had an organized presence on Tiananmen Square beginning in the week of the student hunger strike, claimed thousands of members, published dozens of handbills and political manifestos, and played an important role in organizing demonstrations after the declaration of martial law. The workers' unprecedented political response helped transform a vibrant student movement into the most severe popular challenge to Communist Party rule since 1949.