Opera Choices

Anybody know anything about opera? Which one should we go to? We can go on Fri, Sat, Sun, or Monday night. We have dinner reservations on Sunday night, but we can probably change those. I've never been to an opera before, and I know Prague would be the perfect place for my first experience. I'm leaning towards Dvorak, only because he was Czech. I do like Verdi... and Carmen is very tempting, but only because it's the only one I've heard of before. Is that a good basis for making a decision? (It also means we'll have to change the night we have our dinner reservations for...)

This was disheartening. What is the world coming to?