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.
Metropolitan Opera House (Philadelphia)
The Metropolitan Opera House was built by Hammerstein to be the home of his then new opera company, the Philadelphia Opera Company (POC). Hammerstein hired architect William H. McElfatrick of the firm J.B. McElfatrick & Son to design the opera house in 1907, and construction began the following year. When it opened as the Philadelphia Opera House in 1908, it was the largest theater of its kind in the world, seating more than 4,000 people.