One of the most striking images of the city of Porto and, in particular, of the historic centre is its panoramic appearance, as regarded from the opposite river bank. This is a product of the orographic complexity of a terrain over which the city grew, and where streets, lanes, stairs, squares, yards and alleys articulate and form a dense built mass outlined by the river in the South. The city of Porto thrives in a perfect dialogue with the Douro river: more than being made of gold (ouro in Portuguese, as favoured by tradition), it revealed being hard (from the Latin duris) in its drawing, while ultimately defining a city that expresses itself in different urban landscapes, in high and low elevations.