I’ve been to only a few of these (winking to Andrea, who has probably been to every single one, lucky dog). The most memorable was Paris’ Garnier, where I went on an extensive tour specifically for people who worked in opera. It is an extraordinary building. If opera is the 19th century in music, then the Palais Garnier is the 19th century in stone.
The photos also evoke those haunting pictures of movie house screens by Hiroshi Sugimoto. Those have the added mystery that comes from his having left the shutter open for the entire film, resulting in a blank screen.
Since these empty spaces might seem a bit gloomy, here’s a famous picture of the old Metropolitan Opera House (39th and Broadway) filled to rafters for the final gala performance in 1966, before it moved uptown to its present site. The exciting “new” singer at the gala was Renata Tebaldi, but the singer people went crazy for was Zinka Milanov, who owned the old Met in Verdi. (I have this on good authority, namely my opera-loving uncle, who was there.) She connected to a style of singing that went back to the golden age (or ages), heard in many of the houses above once.