The city of Lisbon is great to explore during a one-day stopover. If you’re looking for cheap flights from North America to Europe, it’s likely that Tap Air Portugal will be one of your top choices. I like Tap Air a lot because they typically have stopovers in Portugal, with enough time to head into the city and explore for a while. This may set some people off from booking their flights though, as most layovers can be from 6 hours to 30 hours. To me, this sounds like an exciting opportunity to explore a bit of Portugal without having to plan a full trip there! My first time in…