Although it wasn't planned, we went to many libraries when we were in the UK and Ireland. The British Library's main exhibit of the key pieces was absolutely amazing. In one room you had a First Folio of Shakespeare's work, 1st editions of Jane Austen, original lyrics from Lennon and McCartney, a Gutenberg Bible and tons more. It was simply awe inspiring.
Socrates's bust at Trinity University, Dublin's Reading Room
Stained glass at John Rylands Library in Manchester