Known as the Osmar circuit in tribute to the creator of the first Trio Electrico.
The Centro area has an urban feel to it, with streets lined with low-rise structures that house low-end commercial shops.
The people that frequent this circuit, or more precisely, those freelancing the streets without an abadá for a bloco or carnival group, tend to be from the lower rungs of the city's socio-economic ladder.
The Campo Grande/Centro circuit is Salvador's traditional carnival circuit. Befittingly, the big name blocos led by axé stars play this circuit on Sunday, Monday, and Tuesday afternoons, the traditional days of carnival. In addition to these popular "axé" blocos, this circuit also hosts bands and blocos that are steeped in tradition and rooted in culture rather than pop, and it is here where one will find Bahia's rich Afro-Brazilian heritage on display.
Thursday night, the first night of carnival, is dedicated to samba and features the blocos de samba Alerta Geral, Amor e Paixão, Pagode Total, to name a few. Here one will find big name sambistas like Dudu Nobre, Arlindo Cruz, and Pêricles (formerly of Exaltasamba).
Saturday night, the Bloco Afros, Ilê Aiyê, Muzenza, Malê de Balê, Didá, amongst others, take to the streets. These huge drum ensembles (with accompanying Afro-Brazilian dancers) dominate the circuit.
Lastly, this Campo Grande/Centro circuit, in keeping with its mission to maintain traditions, nurtures a host of independent trio elétricos. These small trios allow the public to follow (for free) a wide range of musical styles, bringing an eclectic element to the festivities, ranging from the absurd to the sublime.
Geographically, the Campo Grande/Centro circuit runs a 7km loop both beginning and ending at the city's main square, the Largo do Campo Grande. From the Largo do Campo Grande, the circuit runs down Rua Sete de Setembro until it reaches Praça Castro Alves (near Pelourinho, the centro histórico) where it makes a U-turn and returns along a parallel avenue, Rua Carlos Gomez, to Campo Grande.
Note: Since Carnival 2014, the city organizers have modified the layout of this circuit. The Blocos/Trio Elêtricos will now stop playing when they reach the Praça Castro Alves and will longer make the return trip to Campo Grande. Instead Rua Carlos Gomes, the "return leg" of the circuit will now play host to small Fanfarra ensembles, brass marching bands, small blocos afros, etc. This "new" circuit layout is a constant subject of debate and it is possible that this circuit may soon return to it's original format.