Some Mardi Gras history from The History Channel

Mardi Gras and Carnival are the same celebrations.
Though Mardi Gras technically refers only to Fat Tuesday, the Mardi Gras season actually begins on Epiphany, a Christian holiday celebrated on Jan. 6 that is otherwise known as Three Kings Day or the Twelfth Day of Christmas.
In Brazil and many other countries, this period between Epiphany and Fat Tuesday is known as Carnival. Whichever name you prefer to use, the revelries of Mardi Gras last until midnight, when Ash Wednesday ushers in 40 days of Lent.
Mardi Gras may or may not have pagan roots.
A popular theory holds that Mardi Gras’ origins lie in ancient pagan celebrations of spring and fertility, such as Saturnalia and Lupercalia. Some experts contend, however, that Mardi Gras-type festivities popped up solely as a result of the Catholic Church’s discouragement of sex and meat during Lent.
Church reformers may have helped to propagate the pagan rumors, these experts say, in the hope of dissuading pre-Lenten hedonism.
Mardi Gras in New Orleans survived early efforts at suppression.
Mardi Gras got going in New Orleans soon after the city’s founding in 1718. The Spanish, who ruled the Big Easy from 1762 to 1800, apparently cracked down on certain Mardi Gras rituals (though documentation from that period is scarce).
U.S. authorities did much the same after taking control in 1803, banning both masked balls and public disguises. Nonetheless, they eventually accepted the festival’s existence. The first recorded Mardi Gras street parade in New Orleans took place in 1837, by which time the city had transformed from a small backwater into a major metropolis.
Twenty years later, six men organized a secret society called the Mistick Krewe of Comus. By holding a parade with the theme of “The Demon Actors in Milton’s Paradise Lost,” along with a lavish grand ball, Comus reversed the declining popularity of Mardi Gras and helped establish New Orleans as its clear epicenter in the United States.
Other secret societies quickly followed Comus’ lead.
In 1872 the Krewe of Rex and the Knights of Momus began paying for parades and balls of their own. They were followed a decade later by the Krewe of Proteus. Since these early societies were exclusively male and white, women and Black residents formed their own groups, such as Les Mysterieuses and the Zulu Social Aid and Pleasure Club.
Mardi Gras occasionally gets canceled.
Since Comus ushered in the modern era of Mardi Gras in 1857, the New Orleans festivities have been canceled about a dozen times. Most of those cancellations came during the Civil War, World War I and World War II, though revelers also stayed home during an 1870s yellow fever outbreak. A scaled-down version even took place in 2006, just months after Hurricane Katrina flooded the Gulf Coast and killed over 1,800 people. Many in-person celebrations and parades in New Orleans in 2021 were canceled due to the COVID-19 pandemic.
Available mostly during the Mardi Gras season, king cake is typically made with brioche dough. Braided and laced with cinnamon, the dough is then glazed with purple, green and gold sugar or covered in icing in those same Mardi Gras colors.
What really sets king cake apart from other desserts, however, is the small plastic baby hidden inside. Whoever finds the baby in his or her slice must buy the next cake or perhaps host the next party.