Lucia di Lammermoor

From The Metropolitan Opera website: 

The character of Lucia has become an icon in opera and beyond, an archetype of the constrained woman asserting herself in society. She reappears as a touchstone for such diverse later characters as Flaubert’s adulterous Madame Bovary and the repressed Englishmen in the novels of E. M. Forster. The insanity that overtakes and destroys Lucia, depicted in opera’s most celebrated mad scene, has especially captured the public imagination. Donizetti’s handling of this fragile woman’s state of mind remains seductively beautiful, thoroughly compelling, and deeply disturbing.