In case you need a place to stay in Rotterdam, I definitely recommend the Airbnb of John and Marisa. The houseboat is even prettier than in the images, very clean and the location is very peaceful.
There is a supermarket (Albert Heijn) and a metro nearby. The city center is easy to reach on foot. All the rooms are very spacious, and the kitchen is perfect to cook a great meal, it includes all essentials.
The communication with John and Marisa went very smoothly and they replied very quickly to all my questions.
We had such a lovely time in John and Marisa's houseboat, it was a pity that we booked it only for 2 nights, but we will definitely return for more days.
Thank you so much John and Marisa for everything!