the central hall is 120 feet long, 60 feet wide and 90 feet high. on the marble floor, there are two maps of the world with a celestial hemisphere. the western and eastern hemispheres are shown on the maps. the hemispheres detail the area of amsterdam's colonial influence. the terrestrial hemispheres were made in the mid-18th century. they replaced an earlier pair made in the late 1650s. the originals showed the regions explored by the dutch east india company's ships in the first half of the 17th century. this feature may have been inspired by the map of the roman empire that had been engraved on marble and placed in the porticus vipsania, a public building in ancient rome.