Valparaíso represents a distinctive case of growth, inside a remarkable landscape, of an important Pacific Ocean seaport (over the XIX-XX centuries), up to reaching a strategic importance in shipping trade, declined after the Panama Canal opening (1914).
Thus, Valparaíso tells the never-ending story of a tight interaction between society and environment, stratifying different urban and architectonic layers, sometimes struck by disasters and always in danger. The Valparaíso morphology can be roughly divided into two main sectors: flat harbour area and hill quarters. Large neoclassic masonry buildings, some previous colonial style constructions (still standing structures spared by earthquakes and following fires) and more recent architectures take place in the commercial district, with straight streets, highways and rail tracks parallel to the coast.
A wide area is occupied by port facilities up to the waterfront.
Otherwise, the steep forty nine hills, cut by ravines (quebradas) and climbed by narrow and snaky lanes, are deeply filled by small and squat houses, typically made by wooden frames, adobe panels and covered by zinc tinplate (calamina); in addition to those pervading clustered homes, notable historical buildings are present (Figs. 1-7).
This fact makes Valparaíso a city “with and without architects”.

Several old cable cars (ascensores) ascend the slope (Fig. 8).

The historic district (Barrio Puerto, protected by UNESCO) lies in the Valparaíso Southern part and embraces a sector which, starting from the flat, reaches the hills (red line, Fig. 9). Furthermore, the Valparaíso Municipality declared protected area all the city portion within the hills amphitheatre (green line, Fig. 9).

Certainly, the city is subjected to various natural hazards (seismic events, but also tsunamis, landslides, etc.) and anthropic calamities (mainly wild and human-induced fires). These features make Valparaíso a paradigmatic study case about hazard mitigation, and risk factors must be very well evaluated during the restoration phases to be planned in the future.