Fat Tuesday, or Mardi Gras, is the day of celebration that takes place before Lent.

Lent is a Western Christian tradition that begins with Ash Wednesday, and winds up on Easter. The forty days of Lent commemorate the days that Jesus spent fasting in the desert. Shrovetide, or the Pre-Lenten season, begins nine weeks before Easter and concludes on Shrove Tuesday—Mardi Gras.

Mardi Gras wraps up Carnival (also spelled Carnaval), the festive season before Lent. The festivities are celebrated in mostly Catholic and Anglican countries, although Lutherans (Fastelavn), Methodists, and other Protestant denominations also observe the season. Fat Tuesday got its name from the practice of eating rich, fatty foods before the sacrifices and fasts of Lent.

Mardi Gras is celebrated around the world, but most notably in New Orleans, Louisiana, and Rio De Janeiro, Brazil.