Vienna State Opera
The opera house was the first major building on the Vienna Ringstrasse commissioned by the Viennese "city expansion fund". Work commenced on the house in 1861 and was completed in 1869, following plans drawn up by architects August Sicard von Sicardsburg and Eduard van der Nüll. It was built in the Neo-Renaissance style by the renowned Czech architect and contractor Josef Hlávka.
Royal Swedish Opera
The original Stockholm Opera House, the work of architect Carl Fredrik Adelcrantz was commissioned by King Gustav III, a strong adherent of the ideal of an enlightened absolutism and as such was a great patron of the arts. The Swedish Opera company had first been located in Bollhuset, but there was a need to separate the Opera from the theatre and give them separate buildings. Construction began in 1775 and the theatre was inaugurated on 30 September 1782 with a performance of the German composer Johann Gottlieb Naumann's "Cora och Alonzo". 
It was also the place for public masquerade balls, events inspired from the famous opera-balls in Paris, which was open for everyone wearing a mask at a cheap cost and somewhat ill-reputed. 
The building was very imposing with its centre Corinthian tetrastyle portico supporting four statues and topped by the royal crown. The four-tiered auditorium was oval in shape, had excellent acoustics and sight lines. The sumptuous foyer contained neoclassic medallions and pilasters.