Although the climax comes over the weekend nearest to June 24, Bumba takes over the city centre at night for the whole month. Dozens of stalls spring up in the areas where the troupes rehearse before setting off to the two churches in the centre around which everything revolves: the Igreja de SA?o JoA?o Batista , on Rua da Paz, and the Igreja de Santo AntA?nio , four blocks north. Along the waterfront, stalls go up selling simple food and drinks, including lethal batidas with firewater rum - try the genipapo. Many choose to follow the bois, as the troupes are called, through the streets: if you feel less energetic, the best place to see everything is PraA§a de Santo AntA?nio, the square in front of the church where all the bois converge, where you can sit and drink between troupes.

Bumba-meu-boi has a stock of characters and re-enacts the story of a plantation owner leaving a bull in the care of a slave, which dies and then magically revives. The bull, black velvet decorated with sequins and a cascade of ribbons, with someone inside whirling it around, is at the centre of a circle of musicians. The songs are belted out, with lyrics declaimed first by a lead caller, backed up only by a mandolin, and then joyously roared out by everyone when the drums and brass come in. Bumba drums are unique: hollow, and played by strumming a metal spring inside, they give out a deep, hypnotically powerful backbeat.

The troupe is surrounded by people singing along and doing the athletic dance that goes with the rhythm. There are certain old favourites which are the climax of every performance, especially SA?o LuA­s, the unofficial city anthem: SA?o LuA­s, cidade de azulejos, juro que nunca te deixo longe do meu coracA?o - "SA?o LuA­s, city of azulejos, I swear I'll never keep you far from my heart", it begins, and when it comes up there is a roar of recognition and hundreds of voices join in. The sound of the people of the city shouting out their song radiates from PraA§a de Santo AntA?nio across the centre, turning the narrow streets and alleys into an echo chamber.

Bumba-meu-boi starts late, the troupes not hitting the centre until 11pm at the earliest, but people start congregating, either at the waterfront or in the square, soon after dark. Bois don't appear every night, except during the last few days before the 24th: ask at the place you're staying, as everyone knows when a good boi is on. Bumba-meu-boi troupes are organized like samba schools; towns and city bairros have their own, but thankfully the festival hasn't been ruined by making them compete formally against each other. Informal rivalries are intense, all the same, and Maranhenses love comparing their merits: most would agree that Boi de Madre de Deus is the best in the city, but they are eclipsed by the troupes from the interior, Boi de AxixA? and Boi de Pinheiro. The best day of all is June 29 (St Peter's Day), when all the bois congregate at the Igreja de SA?o Pedro from 10pm until dawn.