Xuanwu Lake in Nanjing is the oldest lake in the city. More than 2200 years old, it was originally a marsh formed by faulting to later undergo several transformations to become what it is now. The project considers the lake as a witness to the changes in the city. With its subtle flows, its banks uneven shape, its sedimentation and aquatic sounds, the lake is explored as a medium through which the city is experienced and its history traced. Through the video form, the accumulated visits to the lake act as an important material resource. Observing the mud, the water, the daily changes, and the bumps of the banks construct a story and an archive for the lake and its relation to the city.