I spent three weeks in Guanajuato, Mexico in January 2011. It was a thoroughly delightful experience. Here are a few photos.
The one above is a street I walked down (and up) most days. Guanajuato is built entirely on mountains and the ravines between them. One is always walking either up or down.
Then is my home, Casa Azul. I attended a Spanish language school, and lived with a local family. My bedroom was the top one with a balcony.
There are not many streets that carry automobile traffic, given the topography. There are many, many little pedestrian streets like this one, some of them nearly vertical. It's the only way to get from a car-carrying street to your home.
You may be able to see that the passageway goes all the way up to the pink house, getting steeper as it goes higher. Imagine carrying your purchases up to your house. Imagine moving, and carrying all your possessions.
This is another pedestrian passageway, but not being downtown, like the first one, it is less grand. This one also turns and continues beyond the top of the photo. In a mile-long walk, I may pass a dozen pedestrian streets, some smoother, some rougher, but all of them steep.