The Catalina Casino is a large gathering facility located in Avalon on Santa Catalina Island,
and is the largest building on the island and the most visible landmark in Avalon Bay when approaching the island from the mainland.

The large building contains a movie theater, ballroom, and formerly an island art and history museum.
The Catalina Casino gets its name from the Spanish and/or Italian language term casino, meaning a "gathering place" or establishment used for social interactions and sometimes shows and dances.
Contrary to the current common English usage of the word casino, this has never been a facility for gambling.

Source: Wikipedia