How Europe’s Opera Houses Won Over Millennials

With an escape game and networking events, La Scala and the Paris Opera are attracting under-30 audiences

Milan

When Niccolò Bulgarini moved here from Florence last year, one of the first things he did was join a group for young opera fans that gave him special access to fabled Milan opera house Teatro alla Scala.

“My grandfather used to hum a bit of Verdi and Puccini,” says the 34-year-old Mr. Bulgarini, a data scientist by training. “I...