On Sept. 13, Mahsa Amini, a Kurdish woman from northern Iran, was in Tehran to visit with her brother. She was walking with him near the entrance to a metro station when members of a “guidance patrol,” also known as the morality police, surrounded them. The religious police complained that Amini wasn’t properly wearing her hijab—a head covering women are required to wear under Iran’s strict religious dress codes. Even though her brother tried to stop them, the members of the patrol arrested Amini and took her away. Three days later, still in detention for the crime of not properly wearing her head scarf, she was dead.

The Iranian government insists that Amini, who was 22 years old and healthy, had a heart attack during that period. Her family, who buried the young woman back in her home town of Saqez on Saturday, were certain they saw signs that she had been beaten.

That evening, protests broke out in Saqez and in towns across Kurdistan. Those protests were put down quickly and forcefully by Iranian police. But instead of stopping, the protests continued to grow. Five days later, they have spread to all areas of the country and turned into a movement that may be the biggest threat to Iran’s brutal religious dictatorship since the Iranian Revolution of 1979.

News of Mahsa Amini’s death seems to have acted like spark in the highly taut society of Iran; a final straw that has snapped the already strained tolerance of people—and especially women—who have come to see their own government as a constant, and demeaning, threat.

While there have been protests in Iran before, including a series of large protests in 2011-2012 that coincided with the “Arab Spring” movement elsewhere, the current protests are notable both for the rapid way they have grown and for the open, sometimes violent, opposition to the government. This isn’t a protest against a particular party or a particular official. It’s a protest that has snowballed into a threat to the entire structure of the theocratic Iranian state. It’s also a threat to the leadership of Sayyid Ali Hosseini Khamenei, who has been “Supreme Leader” of Iran since 1989 when the original religious leader of the revolution, Ruhollah Khomeini, died.

At 83, Khamenei is now the longest serving head of state in the Middle East, and the second-longest-serving leader of Iran in modern history. Most of those protesting in the streets of the Iranian cities have never lived in a nation where Khamenei was not the head of both church and state.

But the level of tension and resentment that has been building among Iranians, and especially among highly repressed Iranian women, seems to have found an outlet, with many now openly expressing their disdain for Khamenei and an urgent need to reform the nation. Both men and women are gathering, marching, and in some instances fighting, in an effort to bring change to the rigid structure of Iran.

Protests in some areas have been joyous, with women symbolically removing and burning their hijabs, while dancing, singing, and applauding each other in what have become public ceremonies of freedom. Others are cutting off their hair and posting images online, making clear their identities as they show their disdain for Khamenei. Protests have also turned violent in many areas, with police firing into crowds. And when police have pushed in to break up ceremonies protesters, men and women alike, have pushed back. At least seven people are known to have been killed by police so far. The actual number is likely much higher.

But with each day, and especially each night, the number of cities where protests are being held seems to grow. The movement that began following the death of Mahsa Amini has touched a deep well of resentment, and a great desire for something better, that is proving very hard for the Iranian leadership to extinguish.

Whether it will continue to grow into something that sweeps aside over four decades of a brutally repressive religious regime, or whether it will be put down by that regime and turn into another footnote among all the protests for freedom that failed, can’t be known at this moment. But in this moment … women are dancing, shouting, marching, and fighting for their freedom at the risk of their lives. Iranian men are supporting them and joining them. And that’s something that seems very much worth noticing.