Porto in a day: the port lodges are in a different city, and the bookshop charges to get in

Cross the bridge to taste port, pay five euros to enter a bookshop, and eat a sandwich covered in melted cheese and gravy. One day on both banks of the Douro.
Oslo in a day: a thousand-year-old ship, a walkable opera roof, and the price of a beer

The Viking ships, the Fram, the sculpture park that is free at all hours, and an honest warning about what things cost here.
Munich in a day: the surfers in the park, the beer garden rule, and the clock that isn’t worth it

A standing wave in the middle of a city park, a law that lets you bring your own food to a beer garden, and one very overrated glockenspiel.
Milan in a day: the Last Supper needs booking months ahead and the roof of the Duomo is the real ticket

Fifteen minutes with a fading fresco, if you booked in February. What to do with the rest of the day in a city that is not trying to be Rome.
Madrid in a day: the Prado is free for the last two hours, and that is a real queue

Free evening entry to the Prado and the Reina Sofia changes the shape of a Madrid day. Here is how to use it, when to eat, and why the covered market by Plaza Mayor is not where locals go.
Lisbon in a day: the free way into the Santa Justa lift, and the tram to avoid

Tram 28 is a pickpocket’s commute and the Santa Justa lift has a back door that costs nothing. A Lisbon day through Alfama, Belem and the custard tart queue that moves fastest.
Krakow in a day: a trumpet call that stops mid-note, and the salt mine 135 metres down

The bugler breaks off in the middle of a phrase, every hour, for a reason from 1241. Plus the market square, the Jewish quarter, and what to do about Auschwitz.
Istanbul in a day: cross to Asia for the price of a bus ticket

The public ferry across the Bosphorus costs the same as a city bus and does what the cruises charge thirty times more for. One day in Istanbul, from Hagia Sophia to a fish sandwich at Eminonu.
Helsinki in a day: a church cut into solid rock, a sea fortress, and the sauna rules

Ferry out to an island fortress, sit in a public sauna with strangers, and see a church blasted out of granite. What one day here actually holds.
Florence in a day: the Uffizi shuts on Mondays and the dome climb has no lift

Two closed Mondays, 463 steps with no way out halfway, and a five-day cathedral ticket that most visitors use for an hour. Planning one day in Florence around what is actually open.