This is the back side of The Great Synagogue, also known as Dohány Street Synagogue.
It is the largest synagogue in Eurasia and the second largest in the world,
after the Temple Emanu-El in New York City.
It was an amazingly intricate structure in an ecclectic mix of styles.
More info here:

http://en.wikipedia.org/wiki/Doh%C3%A1ny_Street_Synagogue