SALVADOR, BRAZIL

The Fest: Two million partiers gyrate down super-crowded streets in this coastal city in northeastern Brazil. The three-day bacchanal makes Rio's festival look like a five-year-old's birthday party.

Party Central: Avenida Sete de Setembro, the street running along the beach.

The Costume: Nothing elaborate here—the Salvadorans wear funky color-coordinated T-shirts that they've ripped and sewn to show off tan lines and curves.

Da Funk: Live bands atop 18-wheeler trailers pound out electric grooves with a heavy bass line and jump-up-and-down beat, a style called axé (pronounced ah-SHAY).

Da Drunk: Caipirinhas—a lethal mix of sugar, lime, and cane liquor.

Historical Twist: Once a major port for the slave trade, the city retains elements of African culture; the drums- and rhythm-heavy music reflects this influence.

The Big Moment: On the morning of Ash Wednesday, the parade groups converge at the lighthouse for one last rowdy run along the beach.

The Hangover: Post-party revelers binge on Bahian specialties like moqueca de peixe, a rich coconut-and-fish stew, and acarajé, a crispy white bean and onion cake stuffed with shrimp.