New Orleans has been inhabited for centuries. In 1718, it became French territory when Bienville founded New Orleans 100 miles from the mouth of the Mississippi River.
Famously on an earlier expedition, Bienville convinced British settlers that the territory was already occupied by French colonists, and the English left New Orleans. We now call that area English Turn.
New Orleans changed hands between the French and Spanish before it was sold to the United States in 1803 for $15 million (approximately $.04/acre). The mélange of people within the city during its founding century contributed to its robust culture.