Why do we celebrate Mardi Gras?

What is the origin of Mardi Gras?
This is a Roman pagan festival celebrating the end of winter, the March Calendes, during which were banned transgressed and authorized disguises. It was later Christianized, to mark the entry into Lent, fasting and prayer which commemorates the 40 days spent in the desert by Christ. "Mardi Gras" precedes Ash Wednesday.
Mardi Gras is therefore a Christian holiday?
Mardi Gras opens the Easter period, until the feast of the Resurrection of Christ. Before the austerity of Lent date makes the joy and abundance. Tuesday is called "fat" in reference to foods considered rich, which we miss during Lent meat, butter, Sugar-... With the Protestant Reformation, which questioned Lent, Mardi Gras is especially identified with the country Catholics and Orthodox. In Anglo-Saxon countries, some Protestants have retained an equivalent, simply titled "Shrove Tuesday": Tuesday confession, absolution or Tuesday.
Where does the carnival tradition?
Mardi Gras is a time carnivals, including Nice, with its floats, and Dunkirk, where they throw herring to the crowd, are famous in France. Carnival comes from the Latin "carne vale", which means "farewell to the flesh." Christians thus mark the deprivation of Lent with a final day of rejoicing, as a food that dress. By disguise, carnival also invites derision.
What about pancakes?
The custom of eating pancakes, waffles, donuts, pancakes or in Anglo-Saxon countries, originally comes from the need to exhaust the reserves of eggs and butter that will not be used during the Lent.