The Chicago Teachers Union went on strike Monday, shutting down the nation's third largest school system. The teachers insist the strike is about helping their students.

"We are out here just trying to make sure that everybody knows that the real reason we are here is for the students," a female teacher picketing outside Steinmetz High School told Labor Beat. "We want to make sure that our students are well taken care of. They need to have the best education possible. This is for them, it is not about us."

The unidentified teacher said the school had about 1800 students and a little over 100 teachers.

"I'm advocating for my students until the very end," she continued. "I am a teacher who is working for smaller classrooms, better and properly maintained facilities, we need to expand our libraries, we need to get more textbooks and up-to-date textbooks -- my economics textbook last year was 12-years-old. We need to make sure we have more nurses, we need to make sure we have more social workers -- our school has one social worker for 1800 students."

"We are trying to make sure our students are properly taken care of, so that they can have the education they deserve."

CTU president Karen Lewis said the 26,000-member union went on strike because the city insisted on implementing a new evaluation system and planned to cut some health benefits for teachers. The city also refused to install additional air-conditioning units in classrooms, limit class size, and hire more social workers, Lewis said.

But Mayor Rahm Emanuel (D) has decried the action as a "strike of choice." Emanuel and Chicago aldermen claimed the city and the teachers' union had agreed on everything except the process for re-hiring laid off teachers and the new evaluation system.

"When you hear that they have agreed on the salary, the other two issues are not strikable issues," Alderman Latasha Thomas told the Chicago Sun-Times. "You’ve got collateral damage: the children. The children are pawns in this, and it was too close to strike."

Watch video, uploaded to YouTube by Labor Beat, below: