This is a typical “alley”/road/walkway of downtown Coimbra.  The buildings are residences, shops, other businesses, etc. 

They are all paved with cobblestones composed of black, grey and white stone roughly chiseled into flat but irregular shapes and laid in various patterns. 

Mostly they are used by pedestrians, but cars will be zipping down them at all hours.  Many are one-way, but others can lead to the need to pass verryyy carefully.