Q: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
The two largest metropolitan areas have subway systems: Lisbon Metro and Metro Sul do Tejo in the Lisbon Metropolitan Area and Porto Metro in the Porto Metropolitan Area, each with more than 35 km (22 mi) of lines. In Portugal, Lisbon tram services have been supplied by the Companhia de Carris de Ferro de Lisboa (Carris), for over a century. In Porto, a tram network, of which only a tourist line on the shores of the Douro remain, began construction on 12 September 1895 (a first for the Iberian Peninsula). All major cities and towns have their own local urban transport network, as well as taxi services.
A:
What are the two subway systems in Portugal?