Bridge with barriers over the Danube Channel before the Rotenturm Gate – Walls and ramparts surround Vienna
Those passing through the city gates had to show various documents such as a passport, a health certificate or a hawker’s licence and to pay customs duties. Some duties were also levied at the so-called Lines (Linien). This name referred to ramparts which had been built in a semi-circle to the west of Vienna for defensive purposes at the beginning of the eighteenth century. The city walls separated the inner city (Innere Stadt) from the inner ring of suburbs (Vorstädte), while the ramparts separated the inner sububs from the rural outer suburbs (Vororte). When the outer suburbs were incorporated into the city of Vienna in 1893 the ramparts were dismantled and a thoroughfare known as the Gürtel was laid out in their place.