Sundays walk are the best! No hurry, nice weather and everybody seems to be more friendly. So I did a nice stroll through the city to the river and walking onto the Willemsplein I noted the museum streetcars or trams. These trams, line number 15, make a tour through the center of Rotterdam with of course an explanation of all the interesting things to see along the way. Nice cars, nice people, recommended!
More info here: https://www.stichtingromeo.nl/en/