Final answer:
The city of Aveiro is called the Portuguese Venice because of its system of canals.
Step-by-step explanation:
The city of Aveiro is called the Portuguese Venice because of its system of canals, similar to the city of Venice in Italy. Canals are man-made waterways that are used for navigation, irrigation, and transportation. In Aveiro, the canals are a prominent feature of the city and are used for both transportation and tourism.