The Bebelplatz formerly known as Opernplatz is a large square at the end of Unter Den Linde, opposite the Brandenburg Gate. It has the Municipal Opera, hence its previous name. On the other side is the Humboldt University, the oldest in the city, and St. Hedwig's Cathedral, a Roman Catholic Cathedral of Berlin. Great for appreciating these monuments. The new name of the square relates to August Bebel, president of the German Social Democratic Party in the nineteenth century. But the place is older, built in 1741, during the reign of Frederick II of Prussia. The square is famous as the site where the Nazis burned 20,000 books in the library of the Humboldt University.