Based on the context and the answer, generate a question. 

Context: Casaer was played by a woman ( the part was written for a castrato , except they do n't castrate people anymore , so they have to use women instead ) , which was interesting to see . Also , there was a fairly small ensemble accompanying the singers , so there were no walls of sounds or great impressive fanfares . But the music was good .

Answer:

A opera



What may I have just seen ?