It's all about the river here. The city rises from its banks: festively colored buildings in seemingly ancient repose, crowned by the twelfth-century cathedral atop the hill, a stately contrast to the carnival of wine and revelry down at the waterfront. In times past the rabelos, cargo vessels native to this river alone, hauled Port wine to this the only port from it could be shipped. This is Porto, Portugal's second city and the source of the the fortified wine that has made the country famous in the hearts and palates of generations of connoisseurs around the world. This is what we found to do -- and, critically, what not to do -- when visiting.