About 80% of the population of Porto, Portugal, identifies as Catholic. For those who practice their faith, they get to choose from 30 main churches in which to do it. These stretch back centuries, the oldest of which is nearing its 1,000th birthday. I had the good fortune to visit many of them as I hiked up and down the city’s hilly streets and passageways, never failing to be impressed by their often-extravagant interiors. Read about the top five churches in Porto >