Most of us don’t have the luxury of unlimited time to explore a city – to see the key sites and then spend a few leisurely weeks of wandering aimlessly and discovering the hidden places of a destination at our own pace. In most cities, the key sites are pretty darn obvious. You’ll definitely spot the Eiffel Tower when walking the streets of Paris, and while you actually have to look to find the few remaining sections of the Berlin Wall, it’s still pretty easy to find. In many cities you can spontaneously decide to take one of those “Hop On, Hop Off” bus tours that take you around the…