The Room Beneath the Fortress

The Portuguese built an underground chamber in El Jadida in the early 16th century. Nobody is entirely sure what it was for.

The Cisterna Portuguesa sits beneath the old Portuguese fortress of Mazagan — now the medina of El Jadida, a UNESCO World Heritage Site — and it is one of the most photographed interiors in Morocco. The room is a Gothic hall supported by 25 stone columns arranged in a grid. A shallow layer of water covers the floor, and the columns are reflected so precisely that the room appears to extend infinitely downward. A single oculus in the ceiling lets in a column of light.

The standard explanation is that it was a cistern — a water storage tank for the garrison. A more recent theory is that it was originally an armoury or warehouse, converted to water storage later. The Gothic vaulting and the scale of the room suggest something built with more ambition than a water tank typically receives.

The Portuguese held Mazagan from 1502 to 1769, when Sultan Mohammed III laid siege to the fortress and the Portuguese evacuated by sea, destroying as much as they could on the way out. The cistern survived because it was underground. It was rediscovered in 1916 when a merchant noticed his wall was damp.

Orson Welles filmed a scene here for Othello in 1949 — the same production that used Essaouira's ramparts. The light falling through the oculus onto the still water made the room cinematic without any set dressing.

The cistern is small. You descend a staircase, stand in the room for five minutes, take a photograph, and leave. But the five minutes stay. The silence, the water, the light, the repetition of columns in the reflection — it is one of those spaces where architecture does something your phone camera cannot explain.