Just as Augustus's "Domus" on the Palatine was connected to the Temple of Apollo Palatinus, so Hitler's palace was to have been connected by a cryptoporticus to the Volkshalle, which filled the entire north side of the forum. This truly enormous building was, according to Albert Speer, inspired by Hadrian's Pantheon, which Hitler visited privately on May 7, 1938. But Hitler's interest in and admiration for the Pantheon predated this visit, since his sketch of the Volkshalle dates from about 1925. Hermann Giesler records a conversation he had with Hitler in the winter of 1939–40, when Hitler was recalling his “Roman Impressions” (""):