This exhibition opens the story of the El Deposito itself through its hidden engineering. At the center of the gallery is a large floor model of the underground reservoir, built to scale, with lighting that highlights its chambers and aqueducts. Archival blueprints, maps, and early survey sketches line the walls, displayed in sequence to show how the reservoir was planned and constructed in the 1870s.

Artifacts retrieved from maintenance works—rusted pipe sections, old bricks, corroded valves—are mounted in glass cases, each labeled with its original function. A side section displays tools used by workers, from chisels and lanterns to protective gear. Enlarged photographs from restoration projects reveal the textures of the cavernous interior, giving visitors a sense of its monumental size.

To enhance the display, a walk-in projection room recreates the reservoir’s tunnels, with sounds of dripping water and echoes, letting visitors feel as if they have descended underground. For context, a corner exhibit compares El Deposito to other 19th-century reservoirs around the world, using visuals and digital interactives.

By focusing on the physical remains and tangible artifacts of the reservoir, “Beneath the Surface” makes visible what usually lies out of sight, emphasizing engineering as both heritage and everyday infrastructure.