The Admiralty building is the former headquarters of the Admiralty Board and the Imperial Russian Navy and since 2012 once again the headquarters of the Russian Navy.The building was re-built in the 19th century to support the Tsar's maritime ambitions. The original design was a fortified shipyard which was later surrounded by five bastions and further protected by a moat.
The Empire Style edifice visible today lining the Admiralty Quay was constructed to Andreyan Zakharov's design between 1806 and 1823. Located at the western end of the Nevsky Prospekt, The Admiralty with its gilded spire topped by a golden weather-vane in the shape of a small sail warship (Korablik), is one of the city's most conspicuous landmarks and the focal point of old St. Petersburg's three main streets - Nevsky Prospect, Gorokhovaya Street, and Voznesensky Prospect - underscoring the importance Peter I placed on Russia's Navy.
References:Rosenborg Palace was built in the period 1606-34 as Christian IV’s summerhouse just outside the ramparts of Copenhagen. Christian IV was very fond of the palace and often stayed at the castle when he resided in Copenhagen, and it was here that he died in 1648. After his death, the palace passed to his son King Frederik III, who together with his queen, Sophie Amalie, carried out several types of modernisation.
The last king who used the place as a residence was Frederik IV, and around 1720, Rosenborg was abandoned in favor of Frederiksborg Palace.Through the 1700s, considerable art treasures were collected at Rosenborg Castle, among other things items from the estates of deceased royalty and from Christiansborg after the fire there in 1794.
Soon the idea of a museum arose, and that was realised in 1833, which is The Royal Danish Collection’s official year of establishment.