Die Fledermaus
metopera.org
From The Metropolitan Opera website:
The supreme example of Viennese operetta, Die Fledermaus both defines and transcends that genre. Its story centers on a magnificent masked ball, given by a Russian prince, that brings together all the main characters in various disguises. The three-act journey from boudoir to ballroom to jail provides ample opportunities for farce and humor, but also for genuine human emotion and a surprisingly realistic view of urban life.