This topographic street plan of Porto was printed on two sheets by the General Staff of the Soviet Union in 1979.
The map is in the Russian language. It is printed in 10 colours, and is extremely detailed, with a contour interval of 2.5 metres. Buildings are classified by their function and material, roads by their width and material, and fields and forests by leaf type. There is a short text which describes the district, the city, its places of importance, and infrastructure (factories, power stations, and hospitals); and indexes to streets and major buildings.
Porto 1 
Porto 2
Many other topographic maps of Portugal are available from TROPICARTA (requires Chomikuj account).