What is a (MC) Master Class? How is it different?

A Zumba® Fitness Master Class is a public event that anyone may attend (age restrictions may apply in some cases).  A Zumba master class does not describe an advanced or pro-level class. It is also more than just a typical Zumba class you take during the week.  The question that usually follows is, “how does a Zumba® Fitness Master Class differ from my regular weekly class?”  This is best explained by the man who created Zumba® Fitness:
Zumba® Fitness creator, Alberto “Beto” Perez, once said that a Zumba® master class is “a class that is much more than just the usual ‘weekly’ class. There must be something much more phenomenal about the class — that makes it special or unique from a regular weekly class.”
“In other words, a Zumba master class is an event that might feature a special guest instructor from another city, a group of local or guest instructors, a special reason for the class (like a grand opening of a gym or studio), or some other element that might make the class unique or different from a regular Zumba class.”