The Water square Benthemplein is a unique innovation in the world: it combines water storage with urban public space in one project.   The water square offers a solution for the climate problem of intense rainfall. It creates extra space for water without sacrificing public space. Even better it is a new great public space for the city.   Is it a building? Well yes and no. No because it is public space that is accessable for everyone. And YES because it is a work of engineering: a construction that is pressed into the ground to be able collect strom water.   The water square is being intensively used by students, skaters and other sporty kids. It has been created in an inspiring participation trajectory with the entire neighborhood.   When it rains hard it relieves the entire city quarter by collecting all the rain. After the rain the water seeps back into the soil or to the open water of Noordsingel. So it is also good for keeping ground water at level and improves open water quality.   The square is a true innovation and good promotion for the water skills of the Netherlands and especially of Rotterdam as its  smartest city.