Located in the Castellana area, this is the main exhibition space of the Canal Foundation. It was created in 2000, by water company Canal de Isabel II, as part of its social commitment to the Autonomous Community of Madrid.

This 2500 m2 space is located in an old ‘aljibe’ or water deposit cistern, with 144 brick arches each 7.5 metres tall. This underground tank once met the drinking water needs that arose when the city of Madrid expanded in the 19th century. Every year, it organises a large-scale exhibition on topics related to history, archaeology, ethnography, or art. Some of its most prominent exhibitions have been the “Warriors of Xian", "Treasures of the World's cultures", “Auschwitz: Not long ago, not far away", and "Game on, the history of the video game".