Rotterdam has an extensive public transportation system, including buses, trams, and the metro. A day ticket costs €8.00 and allows unlimited travel on all modes of transportation. Alternatively, you can rent a bike to explore the city at your own pace. Renting a bike costs around €10-€15 per day, and most bike rental companies offer guided tours.
If you have more time, consider visiting the Maritime Museum, the SS Rotterdam, or taking a boat tour of the Rotterdam Harbor. For those with less time, skip the Zoo or Museum Boijmans Van Beuningen, or allocate less time to each attraction. Additionally, Rotterdam is a foodie's paradise, so don't forget to try some of the local delicacies, such as stroopwafels, Hollandse Nieuwe, and bitterballen.