The Zeughaus (old Arsenal) in Berlin, Germany is the oldest structure at Unter den Linden. It was built by the Brandenburg Elector Frederick III between 1695 and 1730 in the baroque style, to be used as an artillery arsenal for the display of cannons from Brandenburg and Prussia. The first building master was Johann Arnold Nering. After his death in 1695, he was followed by Martin Grünberg, then Andreas Schlüter and finally Jean de Bodt. Andreas Schlüter designed the keystones above the round-arch windows in the form of heads of giants. Georg Friedrich Hitzig (1811-1881) constructed the monumental flight of steps to the upper floor of the north wing and also a roof over the courtyard.