Clementinum is a complex of baroque buildings, which once housed the Jesuit College, and now houses the National Library of the Czech Republic. The complex is located on a large area and is limited to the streets of Charles, Seminarskaya, Crusaders, Platnerzhskaya and Marianskaya Square. The name "Clementinum" comes from the medieval chapel of St. Clement (Clement), who stood in this place. It includes: the Mirror Chapel (1724), the Mathematical Museum (1752), the Astronomical Observatory (1722), the University Library (1727), the first meteorological station in Central Europe, which was opened in 1751 and has been conducting daily temperature measurements since 1775.→