The imperial capital of Austria on the Danube, seat of the Habsburgs for six centuries and a UNESCO-listed old town made for walking. Read the Roman fort beneath the Innere Stadt around Saint Stephen's Cathedral, cross the courtyards of the Hofburg to the Imperial Treasury and the Spanish Riding School, and walk the grand Ringstrasse where the city walls once stood. A city of cathedrals, palaces, and boulevards, best taken slowly at your own pace.