Zurich in a day: swim in the river, and understand why everything costs what it does

Public bathing spots on a river that runs through the middle of a financial capital, a Dada bar still trading, and honest numbers on the prices.
Warsaw in a day: the old town is 70 years old and that is the point

Eighty-five per cent of the city was deliberately destroyed and then rebuilt from paintings. What to see, and why the Palace of Culture divides everyone.
Vienna in a day: standing tickets at the opera cost less than the interval drink

The Staatsoper sells standing places for a few euro on the night. Around that queue, a Vienna day runs from the cathedral roof to the Naschmarkt and a coffee house that will not hurry you.
Venice in a day: the day-tripper fee, the €2 gondola, and the church nobody queues for

Venice now charges some day visitors to enter, and the cheapest gondola ride in the city costs two euro and lasts three minutes. What a single day here should actually contain.
Tallinn in a day: an intact medieval town, and a Soviet ruin the tour buses avoid

The old town survived the twentieth century almost whole. Then walk twenty minutes north and see what the other half of the century left behind.
Stockholm in a day: the old town is a tourist trap and the metro is a gallery

Gamla Stan takes ninety minutes and then you should leave. The ship museum, the underground art and the island the locals actually use are elsewhere.
Seville in a day: climb the ramp up the minaret, and do nothing at all from two till five

A cathedral tower with no steps, a palace still used by the royal family, and a heat schedule that decides everything from June to September.
One day in Rome: booking the two tickets that cannot be bought on the door

A single day in Rome works if the Colosseum slot and the Borghese booking are settled before you arrive. Here is the walking order that follows from those two fixed points.
Reykjavik in a day: the pools matter more than the tourist lagoon

Geothermal water, a concert hall made of glass honeycomb, and the northern lights question answered honestly. One day in the northernmost capital.
Prague in a day: walk the bridge at seven, and refuse the first exchange office

Charles Bridge before eight is a different bridge. A Prague day built downhill from the castle, with the tram that does the climbing and the currency law that gets your money back.