It is located beneath the citadel at the heart of the historic Portuguese fortified city of Mazagan.

[5] The cistern has been used as a filming location for several movies, of which Orson Welles' Othello is the best known internationally.

[6] The semi-subterranean chamber has a roughly square plan measuring around 33 to 34 metres (108 to 112 ft) per side, was constructed with five rows of five stone pillars and columns.

[3][7] A round opening in the center of the chamber served to collect rainwater.

[3] The cistern is known today for the visual impression created by the thin layer of water covering the floor, which creates ever-changing reflections from the single shaft of light through the central hole in the ceiling.