Clementinum, Prague

Clementinum fills this Old Town block as a Baroque complex housing the National Library of the Czech Republic. Its scale is startling: after Prague Castle, it is Prague’s largest building complex. The site began with a chapel of Saint Clement in the eleventh century, then became a Dominican monastery before the Jesuits made it a college in 1556.

They brought Charles University’s library here in 1622, and their college joined the university in 1654. A major building campaign from 1709 to 1726 created the Baroque library hall. Its makers included Carlo Lurago, Kilián Ignác Dientzenhofer, and Johann Lukas von Hildebrandt.

Weather observations have continued here since 1775, forming central Europe’s longest unbroken record. The former college is also a national cultural monument.