Karlsplatz city, Vienna#
Licensed under PD
View showing the original above-ground Jugendstil (Art Nouveau) Karlsplatz Karlsplatz, Wien city rail pavillion in Vienna, as well as the present-day underground subway entrance.
Viennas first rail mass transit system opened in 1898; in 1976 it was integrated into the newly established U-Bahn (metro), which is currently about 75 km (46 mi) long.