costumes vary from one region of Brazil to another. In the southeastern cities of Rio de Janeiro, São Paulo and Vitória, huge organized parades are led by samba schools. Those official parades are meant to be watched by the public, while minor parades ("blocos") allowing public participation can be found in other cities. The northeastern cities of Recife, Olinda, Salvador and Porto Seguro have organized groups parading through streets, and public interacts directly with them. This carnival is also influenced by African-Brazilian culture. It is a six-day party where crowds follow the trios elétricos through the city streets, dancing and singing. Also in northeast, Olinda carnival features unique characteristics, heavily influenced by local folklore and cultural manifestations, such as Frevo and Maracatu.