Built around 1514, in what is now the Moroccan city of El Jadida, this was initially an armoury but later became a cistern for water storage. The Portuguese were worried about seige in this dry area. It was forgotten over the years and only found again in 1916. It is a magical place. Cool and dark. The only light from the central opening. There is a fine sheen of water on the floor which reflects everything like a mirror. The architecture is Manueline, characteristic of Portuguese architecture during the years of maritime expansion. The colors are subtle; almost all from the centuries of mould growing here. An amazing, amazing place.