The Vienna National Opera House (Wiener Staatsoper) is one of the world's most famous opera houses, known as the "World Opera Center" and the main symbol of Vienna. The Vienna National Opera House is one of the four largest opera houses in the world. It was built in 1861 and completed in eight years. It is situated on the Circle Avenue of Vienna's Old City. It was originally the Royal Palace Theatre. The Vienna National Opera House (Wiener Staatsoper) is one of the most famous opera houses in the world. It is also the main symbol of Vienna, known as the World Opera Center.