Catalonia is preparing for a critical moment in its history. Officials are holding a non-binding referendum on independence from Spain. But Madrid has deployed thousands of police officers to stop Sunday’s vote. Meanwhile, opponents of independence have rallied in both Madrid – and Barcelona.

School playgrounds across Catalonia are bracing to play a key role in the Catalonian Independence referendum. Teachers, parents, and children have occupied more than 160 schools in the region since classes ended on Friday afternoon. They hope their actions will ensure that voting stations will be open for Sunday’s non-binding referendum. But police have already warned the occupiers they must vacate the premises before the polls open Sunday morning.

“They will come,” parent Josep Jimenz said. “They told us yesterday night. They will come and close the school. We don’t know exactly what is going to happen. There will be many people probably here. If there are too many people, it will be very difficult to close the school.”

The support for an independence referendum was demonstrated again at a final mass rally that took place on Friday evening. Spanish authorities say the vote is illegal and won’t be allowed to go ahead. But Catalan groups remain confident it will.

“We are convinced that we will have a great democratic day and that the Spanish state will accept this and that there will not be any problem,” Jordi Sanchez, the president of the Catalan National Assembly, said. “There will be no more repression, no more limits on the law.”

Thousands of extra police have been deployed to stop the referendum from proceeding. Pro-Spanish nationalists were out in force in Madrid to protest against the referendum. Those scenes were repeated, albeit on a smaller scale, in Barcelona.

“We are here because we are Catalans and we are proud of being Spanish,” one demonstrator said. “Catalonia has been a part of Spain for five centuries. You can be Catalan and Spanish and you can be proud of being Catalan and Spanish.”