The country’s most famous university is an oasis of Victorian tranquillity in the middle of the city. Founded by Elizabeth I in 1592, most of the stunning buildings and landscaped squares date from the 18th and 19th centuries, but the campus’ single biggest attraction is much, much older – queue up to gape at the Book of Kells, one of the world’s most extraordinary illuminated manuscripts. Thirty-minute walking tours are available, see website for details.