Mardi Gras 2013: What it is and why we celebrate it (PHOTOS)

Mardi Gras revelers walk through the French Quarter on Mardi Gras Day February 12, 2013 in New Orleans, Louisiana. Fat Tuesday, the traditional celebration on the day before Ash Wednesday and the begining of Lent, is marked in New Orleans with parades and marches through many neighborhoods in the city.</p>

Mardi Gras revelers walk through the French Quarter on Mardi Gras Day February 12, 2013 in New Orleans, Louisiana. Fat Tuesday, the traditional celebration on the day before Ash Wednesday and the begining of Lent, is marked in New Orleans with parades and marches through many neighborhoods in the city.

Mardi Gras, a day of celebration around the world known for its huge parades and parties in places like New Orleans, Venice and across Brazil, is a Christian holiday that has become a cultural curiosity even for those who don't celebrate.

According to History.com, Mardi Gras is thousands of years old and has links to pagan spring and fertility rites. Today's festivities are mostly celebrated in countries with large Roman Catholic populations and marks the day before the season of Lent begins.

More from GlobalPost: Mardi Gras: 5 must try traditions

If you're in Brazil, you can head to Carnival in any city and become one of its revelers, dancing samba in colorful costumes to the beat of the drums, or just watching from the sidelines if you prefer.

Those in New Orleans had to dodge some rain this year, but that didn't stop them from heading out to one of the world's most famous Mardi Gras celebrations. The flesh-filled parade went off without a hitch.