[{SlideShowNav}] !!!Karlsplatz city, Vienna [{Image src='700au.jpg' width='800' alt='Karlsplatz city, Vienna' class='image_left' height='590'}] [{SET customtitle='Karlsplatz city, Vienna'}] \\ View showing the original above-ground Jugendstil (Art Nouveau) Karlsplatz [{GoogleMap location='Karlsplatz, Wien' zoom='16'}] 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.