São Luís  is a hothouse for popular and religious celebrations. While nobody ever talks about its Carnaval, in recent years, traditional blocos (groups) and bandas have been resurrected. The resulting festivities give you a real taste of Brazilian Carnavals of yore.
Brass bands play marchinhas (marches) and traditional Afro blocos pound out tambor-de-crioula rhythms while lithe dancers whirl like dervishes. Residents of all ages take to the streets of the centro histórico and Praia Grande in masks and sequins. The atmosphere is heavy on alegria and light on mayhem.
Even bigger and more spectacular than Carnaval the not-to-be-missed Bumba-Meu-Boi festivities, which take place in June. São Luís  isn’t the only place in Brazil  that hosts Bumba-Meu-Boi, but it is the definitive place to observe one of the country’s most spectacular and captivating spectacles, combining music, art, and pageantry.
Drawing on indigenous, African, and Portuguese folk elements, Bumba-Meu-Boi consists of a series of theatrical dances performed over several nights in mid–late June. Visually stunning, the festivities feature troupes of well-known folk characters in brilliant costumes. They are accompanied by musicians playing brass instruments and drums, the most unique of which is the deep, throbbing bumba.
The festa revolves around the magical tale of a plantation owner who leaves a slave to take care of his prize bull (boi), which dies and then comes back to life with the help of forest spirits.
Bumba-Meu-Boi troupes are like samba schools. There are many groups within the city and rivalries exist as to who can put on the most dazzling spectacle featuring the story’s characters. The bois are exceptionally resplendent — their costumes are festooned in ribbons, sequins, and embroidery fanciful enough to make a Parisian couturier’s jaw drop. It’s impossible to resist joining in the dancing and singing that invades the streets of Praia Grande and Centro.
If you miss the main celebration, you can catch Bumba-Meu-Boi troupes performing throughout the month of July at the Convento das Mercês.