Vienna U-Bahn U1

U1 is the Vienna U-Bahn line that quietly does a lot of visitor work. It runs through Stephansplatz, Karlsplatz, Praterstern, and Donauinsel, then keeps going toward Oberlaa in the south and Leopoldau in the north.

For a normal trip, it is the line for the old center, the Prater side, and the Danube Island. During Donauinselfest, it becomes the festival line, which is useful to know before you accidentally book a day when half the city is riding the same corridor.

U1 feels like modern, competent metro Vienna: not the quirky one, not the scenic one, just the line that makes the city easy.