Dante in Inferno: the devil is in the detail (of perspective)

One of my favourite parts of Dante's Commedia is the end of Inferno, canto 34. Having surveyed all nine circles, the two poets reached the abode of Lucifer, lo ’mperador del doloroso regno. They went down Satan's fur and out of Hell, but, as Dante soon learned, they crossed the centre of the Earth and experienced a reversal in gravity, causing Satan to …