Visiting Porto, Portugal, is a reminder of Portugal’s historic importance as a world trading centre for over two thousand years and its dominance in the 16th century.  The historic district is a UNESCO World Heritage Site.  For wine lovers, Porto is the home of the one and only Port wine, with Vila Nova de Gaia across the Douro River being the district where most of the major Port houses cellar and age their wines.  I have stayed at the Grande Hotel in the shopping district (about a mile north from the bridge), but if you are visiting …