This article describes when teachers in Detroit, Michigan and Gary, Indiana went on strike in September 2006, which have resulted in the closure or relocation of 35 schools to other campuses since the end of the 2004-05 school year. The 2006-07 school year has brought with it a fresh wave of labor unrest, as teachers in districts large and small went back to school without new contracts and thousands took to the picket lines. Union officials who track teacher protests say labor rumblings are common at the beginning of a school year because contracts often have expired at the end of the preceding year, and labor and management have not been able to reach an agreement over the summer. Union officials also say that the ability to strike is an important tool for teachers when districts seek to cut into salaries and benefits.