New Orleans: Say "Mardi Gras" in the U.S., and everyone thinks of New Orleans, with its masked partygoers. The city's pre-Lent Carnival is tamer now than it was before the 2005 hurricane. But it's still a blast (mardigrasday.com). Be sure to stop by Mardi Gras World, a museum showcasing famous floats and memorabilia (mardigrasworld.com).
Belgium: Binche—a town close to the border with France—has held an annual pre-Lenten festival since the 16th century. The must-see event is the March of the Gilles, a parade of men and boys wearing brightly colored costumes with wooden clogs (carnavaldebinche.be). Meanwhile, a few Sundays before Easter, residents in the community of Stavelot interrupt Lent with a festival. White-robed figures go on parade, and one of them may smack you with a dried pig's bladder—or something just as yucky (laetare-stavelot.be).
Brazil: Considered the granddaddy event, Rio de Janeiro's sultry Carnaval pulses to a samba beat, the ritual music rooted in Afro-Brazilian culture. Free street parties are easy to find, but the main event is a competition between samba performers in a 70,000-person venue, the Sambodromo, with advance-purchase tickets from $110 (rio-carnival.net).
Canada: Quebec City claims to have the most visited Carnival in the Northern Hemisphere. Residents build ice and snow sculptures as large as real-life castles, and on the last day, canoes race in the ice-choked St. Lawrence River (carnaval.qc.ca).
Colombia: If you go to the Carnival party in the Caribbean coastal city of Barranquilla, don't be surprised if someone tosses a garland of flowers around your neck while you're standing on a cobbled street listening to a mix of Colombian funk and folk music (colombia.travel).
Germany: In Cologne, Kölner Karneval is a rowdy week for many adults, with bars suspending their usual closing times. But kid-friendly events include a parade on the Monday before Ash Wednesday, when Kamelle (candies) are tossed from floats. Some of the traditions have been passed down since at least the Middle Ages (koeln.de).
Italy: In Venice during Carnevale (from the Latin for "removal of flesh"), you'll see the occasional costumed figure in St. Mark's Square. But masked participants can be found in all of the major piazzas. There are no private cars in this water-bound city, so Carnevale revelers done up in exotic attire must walk to their fancy-dress balls, giving onlookers a chance to peek at them (carnivalofvenice.com).
Mexico: Residents of the western coastal city of Mazatlán are fiercely proud of their Carnival. Costumed performers surge southward along the Pacific coastline, followed by a fireworks and laser-light show, best viewed along the harbor (gomazatlan.com).
Trinidad and Tobago: Throwing the biggest pre-Lent celebration in the Caribbean, capital city Port of Spain showcases stilt-walkers and other performers. The ingenious costumes typically satirize the former British colonial authorities (gotrinidadandtobago.com).