Teachers and students have bonded together in Jefferson County, Colorado to protest a conservative school board's proposal to change the history curriculum. The students have staged multiple walkouts and teachers shut down two high schools on Monday with massive sick outs, the second time in two weeks.

Golden and Jefferson high schools canceled classes after 73 percent and 81 percent, respectively, of the teachers called out, according to The Guardian. The teachers first staged a "sick-out" on Sept. 19 that also caused two schools to close.

Students across the county staged walkouts every day last week. About 100 students walked out of Evergreen High School on Sept. 22, followed by 200 more the next day at five different schools. Another 700 students walked out of three more high schools on Sept. 24 and gathered outside to chant and hold up signs to ask for support from passing motorists. By the end of the week, more than a thousand were leaving school to participate in the student protests.

The school district did not punish students for their participation, but they will receive unexcused absences unless their parents call in to excuse their missed classes, according to CBS News. Each teacher absence will be independently reviewed, and teachers could be docked pay if their absence falls outside of the collective bargaining agreement, district superintendent Dan McMinimee told The Guardian. The district may take further action if the sick outs continue.

The Jefferson County School District school board has made a number of controversial decisions since members' election last November. The conservative majority, led by chairman Ken Witt, Julie Williams and John Newkirk, have appointed a new superintendent and bailed out two faltering charter schools. They also chose to include students' state test results in teachers evaluations, a move that teachers were told wouldn't happen.

The kicker came when Williams proposed a review of the Advanced Placement history curriculum. She wants the history classes to "promote citizenship, patriotism, essentials and benefits of the free enterprise system, respect for authority and respect for individual rights," according to curriculum review proposal. She doesn't want the courses to "encourage or condone civil disorder" that could lead to breaking the law.

"There are things we may not be proud of as Americans," Williams told Chalkbeat Colorado, a school news website. "But we shouldn't be encouraging our kids to think that America is a bad place."

Supporters of the conservative board members believe the teachers' unions are behind the protests. On the other side, some parents of Jefferson County students believe the board members' campaigns were supported by well-funded conservative groups.

The board's proposed review of the AP course lines up with the Republican National Committee recent condemnation of the new AP course standards, set by the College Board. The RNC adopted a resolution at a conference in March that referred to the AP U.S. History course as a "radically revisionist" and anti-American view of history, according to The Guardian.

Students first launched a peaceful protest before they started the walkouts. In response to Williams comment, "I don't think we should encourage our kids to be little rebels," students chose to dress up and attend school as famous American agitators. The costumes included Martin Luther, Eleanor Roosevelt, Boston Tea Party participants, the Green Mountain Boys, Elizabeth Cady Stanton, Susan B. Anthony and Rosa Parks.

"This is going to affect all students in Jefferson County and across America," Egan Walker, a sophomore at Standley Lake High School, told The Guardian. He started a petition to stop the board's proposed review had received nearly 27,000 signatures of Sept. 26. "If our history textbooks are censored, we won't have the right information. It would affect everyone's education."

A hearing on the proposed review is scheduled to take place on October 2.