Oxford, UK

Oxford sits on the River Thames with roughly 162,000 residents and anchors the oldest university in the English-speaking world, founded around 1096; 72 of its affiliates have won the Nobel Prize. The 1480 Bodleian Library holds about 13 million printed items and is one of six legal-deposit libraries in the UK. Christ Church Cathedral, dating to 1546, doubled as Hogwarts' dining hall in the Harry Potter films, while the 1780 Radcliffe Camera ranks as England's oldest circular library. The 1651 Sheldonian Theatre by Christopher Wren seats 1,200. What is the secret of a city that never stops teaching?