Opera and Ballet of Nations

List of opera houses https://en.wikipedia.org/wiki/List_of_opera_houses

Opera composers by nationality https://en.wikipedia.org/wiki/Category:Opera_composers_by_nationality

List of important operas https://en.wikipedia.org/wiki/List_of_important_operas

10 Classic Operas for People Who Don’t Know Shit About Opera https://www.laweekly.com/music/10-classic-operas-for-people-who-dont-know-shit-about-opera-6015736

Opera by country – the 10 countries around the globe with the most opera! https://www.operasense.com/opera-by-country/

Top 50 operas: These operas span four centuries and give a flavour of […]