Between 1945 and 1965, the company performed on other stages while the theatre building was being restored and expanded to the designs of Bohdan Pniewski, under the supervision of Arnold Szyfman. When the restored theatre was opened to the public on November 19, 1965, it was one of the most imposing and best-equipped state-of-the-art theatres in Europe. The Polish National Opera was the largest theatre in the world.