The Opernhaus (in German) is located on the massive Sechseläutenplatz. Apparently a music festival was held on the square a few weeks ago. It has been the home of the Zürich Opera since 1891, and also houses the Bernhard-Theater and the Zürich Ballet. Sadly they wouldn’t let go in to have a peak and there was nothing on for me to see whilst I was there. Maybe next time.
Ian