The rooms' outerwalls are each filled with 250lbs of insulating polyethylene to protect astronauts during solar flares and damaging ultraviolet radiation.
Japanese designers have transformed the previously grimy space into a light-filled community centre by partially removing the outerwalls, replacing them with glass and lining it with books.
The Inner City covers an area of 2.99 square kilometres (1.15 square miles) and the outerwalls surrounding the city east and west of the Euphrates enclose an area of 9.56 square kilometres (3.69 square miles).