Today, Jackson Square and other places in New Orleans will be full of revelers. No, it’s not a Mardi Gras do-over, it’s the city’s 300th birthday celebration. Sometime in the spring of 1718, ‘La Nouvelle-Orléans’ was founded by French investors. Since then, residents of the Big Easy have chosen May 7 as the day to celebrate the birth of New Orleans. Really, this city doesn’t need an excuse to throw a party, but this one’s going to be big.