Office workers huddle at their windows, peering down in disbelief. Thousands of protesters are marching along S?o Paulo’s main Paulista Avenue, beckoning to them and chanting: “Vem pra rua, vem!” (“Come to the street, come!”)

The slogan has become one of the few elements uniting the disparate groups that have taken to the streets in more than 100 cities across Brazil this month. The protest movement has caught the rest of the world by surprise, not to mention Brazilians themselves.

“That phrase actually comes from a Fiat commercial,” explains Sophia Montero, an 18-year-old student, brandishing a neon pink banner condemning evangelists’ attempts to pass a bill to “cure” homosexuality. “Everyone has been watching the advert on television at home so we started using it. Protesting is still very new for us, so?.?.?.?” She is cut off when a friend pulls her out of the way of another group, this time campaigning against proposals to limit the investigative powers of public prosecutors. Among their banners is another activists’ favourite: “O gigante acordou” (“The giant woke up”), made popular by a 2011 Johnnie Walker commercial.