Simplify the following text for a Grade 9 native English-speaking person.
Original: The Metropolitan Opera Association of New York City , founded April 28 , 1880 , is a major presenter of all types of opera including Grand Opera .
Simplified: The Metropolitan Opera Association is a big organization in New York City which puts on performances of opera . The Metropolitan Opera House ( often simply called : The Met ) is one of the most famous opera houses in the world .