Thousands of teachers in the Carolinas left their classrooms Wednesday and headed to their state capitols to pressure lawmakers to invest more in education, joining the swell of teacher activism that has swept the country since last year.

In Columbia, S.C., a sea of teachers in red — the teacher movement’s signature color — packed the grounds of the capitol, chanting, “This is what democracy looks like!” and “I teach, I vote!" About 180 miles northeast, in Raleigh, N.C., there was a convergence of red-clad protesters downtown. Both groups plan to head back to the classroom Thursday.

LOOK: Video from South Carolina Department of Public Safety shows their estimate that there may be 10,000 people at the #AllOutMay1 teacher's rally at the SC State House. >>>

Posted by WIS TV on Wednesday, May 1, 2019

Wednesday’s job actions affected nearly 1 million schoolchildren, with some schools closed while others remained open but without enough staff. In South Carolina, at least seven districts closed, keeping about 123,000 students out of the classroom, according to the Post and Courier in Charleston. In North Carolina, closures were widespread, with 850,000 students missing class, according to the News & Observer in Raleigh.

It was a historic day for South Carolina’s state capitol, where about 10,000 people gathered for the rally, according to an estimate by the state’s Department of Public Safety. It was one of the largest gatherings ever at the state capitol, matching crowds that convened in 2015 to watch officials take down the Confederate flag that had long flown over the statehouse. It was organized by a teacher-led Facebook group, SC for Ed, mirroring tactics used in other states where laws have weakened labor unions.

Kathy Maness, executive director of the Palmetto State Teachers Association, a professional group, said the rally marked a turning point for educators, who had hosted much smaller weekend rallies in the past while enduring years of stagnant wages and a lack of investment in schools. A Post and Courier investigation, published last year, laid bare how the state had fallen in national rankings on several measures.

“For many years, I have said that teachers in South Carolina have been sleeping giants,” Maness said. “They would go in their classroom, they would do their job and would not speak up for their profession.”

“I think that sleeping giant is waking up.”

The protests in the Southern states signal the continuation of a teacher movement that has emerged coast to coast. Beginning in West Virginia, where teachers successfully pressed for a pay increase early last year, educators have left classrooms in protest on multiple occasions, including in states historically hostile to labor unions. This year alone, there have been at least nine major teacher protests, including a strike in the nation’s second-largest school district, Los Angeles Unified, and a repeat walkout in West Virginia, where teachers protested a bill that would have introduced charter schools and private school vouchers to the state. Oregon teachers could walk off the job next if state lawmakers fail to pass a school funding hike.

The protests Wednesday rankled officials in both states, who said they understood the teachers’ frustrations but opposed their tactics. Republican state lawmakers in North Carolina proposed a ban on school closures for protests, a move that would make it difficult for districts to approve leave for teachers who want to walk out.

Molly Spearman, superintendent of public education in South Carolina, condemned the job action.

“I support teachers using their voice to advocate for needed change and share in their commitment to ensuring reforms become reality,” Spearman said. “However, I cannot support teachers walking out on their obligations to South Carolina students, families, and the thousands of hard-working bus drivers, cafeteria workers, counselors, aides, and custodial staff whose livelihoods depend on our schools being operational.”

North Carolina teachers are calling for a pay increase but also rallying to raise the minimum wage for other school employees and expand Medicaid in the state, which they say will improve the health of students, families and other school employees.

They also are pressing for more counselors, psychologists and nurses in schools. Mark Jewell, president of the North Carolina Association of Educators, said the state’s schools are woefully inadequate when it comes to providing for the mental and physical health needs of children.

“We have horrific ratios,” Jewell said. “Our kids are struggling. Our teachers are struggling.”

North Carolina teachers also rallied last year to press state lawmakers to invest more in schools.

The protests coincide with May Day, also known as International Workers’ Day, a tradition that started in the United States in the 1880s. The teachers join millions of workers across the globe: garment workers in Bangladesh rallying for maternity leave, activists in the Philippines calling for an increase in the minimum wage, unions in Germany warning of the rise of nationalism and demonstrators in Turkey who faced arrest.