Teachers have promised there will be more mega-strikes if the Government doesn't give them better pay and conditions.
Some 55,000 teachers walked off the job on Wednesday, affecting 800,000 students.
For the first time ever, primary and secondary school teachers came together in the hope their strength in numbers simply can't be ignored.
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In Auckland, 15,000 marched up Queen Street.
"Give us more - not just for us, for our children," one protester told Newshub.
The message to the Government is pretty straightforward.
"They need to value teachers, teachers are worth it," one said.
"Not enough resources, not enough time," said another.
Marnie Wilton isn't a teacher, but started a group which backs them. It's got more than 10,000 members so far.
"This is not a teaching crisis, it's a crisis for our kids," she said. "Because we care about our kids, and if we want a decent education we need to give that to them."
Students also made their feelings clear.
"Our teachers are underpaid and our mums, because they're all teachers," one girl said. "We don't have any time with them, and they're always busy with school stuff."
Similar scenes played out around the country, with 47 marches taking place in total.
"If we have to keep striking until we get what we want, we will," one teacher said. "It's hard, I'm not going to lie. I live paycheck to paycheck and it's tough."
The latest offer from the Government is worth $1.2 billion: a $700 million pay offer for primary teachers and $500 million for secondary teachers.
The Ministry of Education has offered pay rises of 3 percent a year for three years, plus an extra step at the top of salary scales that would take the total pay rise for a majority of teachers to 12.6 percent over three years.
It was the fourth offer rejected by teachers.
Most teachers Newshub spoke to say it's not just about more money in their back pocket, but more money for the industry so they can simply do their job properly.
"There's frustration, there's anger, there's a bit of disappointment as well," NZEI President Lynda Stuart said. "There's sadness. But actually, education is in crisis."
Education Minister Chris Hipkins can be in no doubt about the depth of teachers' feelings.
"We have heard that concern," he said outside Parliament while protesters chanted "not good enough".
"I acknowledge you want more progress and you want it to be faster, and I cannot offer you that."
There was a warning for the Minister at Wednesday's protests: this won't be the last of it.
"As far as we can, we're not going to stop," one said.