Mardi Gras is celebrated in New Orleans in mid February. It all started in ancient Rome on the 12th night of Christmas. In French, Mardi Gras means Fat Tuesday, and it is a tradition of using all the butter and fat in the kitchen.
In New Orleans, it start in 1857 as a secret society. The colors for Mardi Gras are purple for justice, gold for power, and green for faith. In New Orlean, they celebrated Mardi Gras with a parade.
For more information about the celebration, watch this video on this video on National Geographics Kids.
Source: National Geographic Kids