The Nativity of Christ Cathedral (Kristus Piedzimšanas pareizticīgo katedrāle) was built to a design by Nikolai Chagin in a Neo-Byzantine style between 1876 and 1883, during the period when the country was part of the Russian Empire. It is the largest Orthodox cathedral in the Baltic provinces built with the blessing of the Russian Tsar Alexander II on the initiative of local governor-general Pyotr Bagration and bishop Veniamin Karelin. The Nativity of Christ Cathedral is renowned for its icons, some of which were painted by Vasili Vereshchagin.
During the First World War German troops occupied Riga and turned its largest Russian Orthodox cathedral into a Lutheran church. In independent Latvia the Nativity of Christ Cathedral once again became an Orthodox cathedral in 1921. Archbishop Jānis Pommers, a native Latvian, played a key part in the defence of the cathedral. In the early 1960s Soviet authorities closed down the cathedral and converted its building into a planetarium. The cathedral has been restored since Latvia regained independence from the Soviet Union in 1991.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.