Dublin is Ireland’s largest city and also its historical, political, artistic, cultural, economic, and industrial centre. It is one of the youngest cities in Europe, with almost 50% of the population aged under 25. There is a traditional divide between the Northside and the Southside, separated by the river Liffey which flows through the centre of the capital. Dublin has an impressive literary history, having produced such prominent writers as Nobel Prize winners William Butler Yeats, George Bernard Shaw and Samuel Beckett, not to mention Oscar Wilde Jonathan Swift and even the creator of Dracula, Bram Stoker. Dublin Zoo, situated in Phoenix Park, is one of the oldest zoos in the world. The post-boxes on Dublin’s streets are coloured green. They were originally red, during British rule, but were repainted green after independence.