The first two are not so far from my Stadtschloss - since they three are on the same square. The Alter Markt is the location of both the Marble Obelisk and the Church of St. Nicholas.
Uploaded on December 25, the Marmorobelisk was my small gift for Christmas. The monument was erected in 1753 by order of Frederick II, by then King in Prussia. It's on the middle of the Old Market, facing both the City Palace to the south and the Nikolaikirche to the north. Construction of the latter began in the 1830s under direction of Karl Friedrich Schinkel, who would not live to see his last work finished. After his death in 1941, his students Ludwig Persius and Friedrich August Stüler oversaw the completion of the neoclassical church, and the dome that was planned by Schinkel.
Regarding the Belvedere auf dem Klausberg, its construction was commissioned by Frederick II to Architect Georg Christian Unger (who built also the Royal Library in Berlin), and was finished in 1772. King Frederick William IV had the Belvedere as an important part of his planned Triumph Avenue that, however, was never realized. The building was to be the end of the Avenue that would have run from the Triumphtor.
The attack carried out by RAF on April 14, 1945 left the Nikolaikirche heavily damaged and the Obelisk with minor scars. The Belvedere, that escaped bombing, was shelled by the Allies by the same time and reduced to rubble, being the staircase the only recognisable remains.
Restoration of the Nikolaikirche and Marmorobelisk begun in the early 1950s, while the Belvedere had to wait until 1990, when the Stiftung Messerschmitt financed the reconstruction. When finished, it was transferred to the Prussian Palaces Foundation Berlin-Brandenburg.