The north of Portugal is the birthplace of the most famous wine. The Douro reaches Porto, irrigating the vines that grow on terraces, and the district of Vila Nova de Gaia is home to wineries, taverns and lots of fun. In the centre of the city, the huge Clerigos Tower, 76 metres high, is used to navigate through the old streets and neighbourhoods of this city; which has been declared a World Heritage Site. Libertad Square, the Stock Exchange and the church of San Francisco are all worth visiting.