It is New Orleans, Louisiana, United States of America. You can use Google Maps to see exact location of 90° W 30° N. File is attached below.
Mardi Gras is one of the most popular festivals over the world. The parades are organized by social organizations and follow the similar route annually. Most popular streets for celebration are Bourbon Street and upriver side of French Quarter.
In pop culture, you may have heard about this festival in popular TV series "The Originals", spin-off of the "Vampire Diaries".
Jazz Fest is celebration of music and culture all over the state. There you may hear to different kind of music, yet jazz, both traditional and conteporary, is left as a basis. Usually the celebration is big, with several stages and huge amount of food.