Throughout modern history, rivers have been used as transportation networks and border spaces, allowing cities to sprawl and urban prosperity to thrive. At the same time, the material, energetic qualities of rivers, their circulatory power, enigmatic behavior and endless life forms tend to be overlooked. What story does the River Tagus tell us about the twin cities of Lisbon and Almada when its tangible, effervescent characteristics are permitted to rise to the surface? An immersive work for headphones, Knowing water takes the listener on a sonic journey to the riverbed. Exploring the subterranean space in which both Lisbon and Almada are contained, it asks questions about the future of our cities and how water — in all its multivalence — might become more knowable to urban planning. The piece is available in two versions: Portuguese and English. Listeners are encouraged to experience the work as they cross the Tagus by boat.