Hundreds of Denver-area high school students walked out their classrooms in a mass protest against what they call an attempt to censor their history curriculum by refocusing it on topics that promote citizenship, patriotism and obedience.

Students at six Denver-area highs schools walked out their classrooms en masse, protesting a plan by the conservative-majority Jefferson County school board to push for curriculum changes to Advanced Placement history courses to promote patriotism and deference to authority. The proposed changes would include the removal of topics that could ‘encourage’ civil disobedience from textbooks and materials.

The protest was organized through social media, encouraging students to stand outside the Jefferson County School Administrative Building with placards which read “People didn’t die so we erase them,”“Educate free thinkers,”“There is nothing more patriotic than protest,” and “History is History.”

The student protest comes after teachers at two schools caused a shutdown the week before when they staged a sick-out over the curriculum changes, which the school board says provides a balanced view of American history.

“I understand that they want to take out our very important history of slavery and dropping the atomic bombs on Hiroshima and Nagasaki because it portrays the US in a negative light," a high school senior, Casey McAndrew, told CNN.

The proposal calls for establishing a committee that would regularly review texts and course plans, starting with Advanced Placement history to make sure materials “promote citizenship, patriotism, essentials and benefits of the free market system, respect for authority and respect for individual rights,” and don’t “encourage or condone civil disorder, social strike or disregard of the law.”

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“The nation's foundation was built on civil protests,” Tyrone G. Parks, a senior student told the Associated Press. "And everything that we've done is what allowed us to be at this point today. And if you take that from us, you take away everything that America was built of."

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Those students participating in the protest will not be punished but will receive unexcused absences unless their parents request permissions for missed classes, according to school district spokeswoman Lynn Setzer said.

Meanwhile, Jefferson County Superintendent Dan McMinimee tried to calm the tensions saying that no changes in the curriculum have been finalized and renewing his offer to continue discussions on the issue.