During my one month stay in Lisbon, I've taken a lot of tram ride, between Belem, where the airbnb was, and Lisbon city. Lisbon is one of the only cities where you still see those vintage trams as daily transportation, not just for tourists. Although many of those old trams are now also replaced by bigger modern ones or even buses. I'm a bit car sick, so I prefer trams to buses, and even prefer old wooden trams to newer ones.
Every time I visit Lisbon city, I took those cute trams. There are a few elevator trams to connect the upper part and lower part of Lisbon, as the city is built on seven hills, some of the roads in the old town can be rather steep. I bet if you live there for a years or so, you get fit by walking up and down those hilly roads every day!
Elevator trams, there are four of them, I visited three.