Furthermore on Bebelplatz the Berlin State Opera ( No. 7 ) , colloquially called Lindenoper , St. Hedwig 's Cathedral and the Altes Palais ( No. 9 ) , favored residence of Emperor Wilhelm I ; in the north the main building of the Humboldt University ( No. 6 ) and House I of the Berlin State Library ( No. 8 ) .
Furthermore on Bebelplatz the Berlin State Opera ( No. 7 ) , coloquially called Lindenoper , St. Hedwig 's Cathedral and the Altes Palais ( No. 9 ) , favored residence of Emperor Wilhelm I ; in the north the main building of the Humboldt University ( No. 6 ) and House I of the Berlin State Library ( No. 8 ) .