Step up to a traditional samba circle in Brazil and you’ll find this: a group of 5 to 15 men, each playing an instrument — a tambourine, a cavaquinho, a drum. Then you’ll typically see women, not playing music, but rather shimmying in the front row of the crowd, dancing to the pounding syncopations. The samba circle, or roda de samba, is a Unesco-recognized part of Brazil’s cultural heritage. These communal releases of weekday worries crop up across the city regularly. The samba circles are free, they’re rowdy and, increasingly, they’re changing.