The unrest is hitting the nation as it hosts the Confederations Cup soccer tournament with tens of thousands of foreign visitors in attendance. It also comes one month before Pope Francis is scheduled to visit Brazil, and ahead of the 2014 World Cup and 2016 Olympics, raising concerns about how Brazilian officials will provide security.
Mass protests have been rare in this country of 190 million people in recent years, and the mushrooming demonstrations of the past week caught Brazilian government officials by surprise while delighting many citizens.
"I think we desperately need this, that we've been needing this for a very, very long time," said Paulo Roberto Rodrigues da Cunha, a 63-year-old clothing store salesman in Rio.
Despite the energy on the street, many protesters said they were unsure how the movement would win real political concessions. People in the protests have held up signs asking for everything from education reforms to free bus fares while denouncing the billions of public dollars spent on stadiums in advance of the World Cup and the Olympics.
"We pay a lot of money in taxes, for electricity, for services, and we want to know where that money is," said Italo Santos, a 25-year old student who joined a rally by 5,000 protesters at Salvador's Campo Grand Square.
But many believe the protests are no longer just about bus fares and have become larger cries for systemic changes.
"This is the start of a structural change in Brazil," said Aline Campos, a 29-year-old publicist in Brasilia. "People now want to make sure their money is well spent, that it's not wasted through corruption."
Associated Press writers Marco Sibaja in Brasilia, Bradley Brooks and Stan Lehman in Sao Paulo and Ricardo Zuniga in Salvador contributed to this report.