A workers entrance is seen locked in a long-closed General Motors plant in Lansing, Michigan June 1, 2009. General Motors Corp filed for bankruptcy on Monday, forcing the 100-year-old automaker once seen as a symbol of American economic might and dynamism into a new and uncertain era of government ownership. The bankruptcy filing is the third-largest in U.S. history and the largest ever in U.S. manufacturing. REUTERS/Mark Blinch (UNITED STATES BUSINESS EMPLOYMENT TRANSPORT)