Hungary: Pannonhalma Archabbey
The imposing cathedral-like complex stands on top of a 244m/700ft high hill above the flat surrounding countryside. This is perhaps the most important and one of the oldest buildings in Hungary and a subject of national prode. The Abbey was founded in 996AD and is now the second largest abbey in the world (archabbey means a fortified abbey, as the building was reinforced during the Middle Ages against the Ottoman attacks). It was also significantly modified with baroque architecture in the 17-18th centuries, to the point where it looks rather modern today. Inside, there is a medieval crypt, a basilica, a cloister, and – most importantly – a library containing over 360,000 ancient books, including the first book in Hungarian from 1055. It’s a UNESCO World Heritage Site.