From ancient to postmodern, these spiral staircases span the spectrum from wonderfully worn to pristinely perfect. Warning: viewing so many in a row from above can have a dizzying impact on the onlooker. Don't trip!
Watch where you tread: some of these stairs have been climbed by kings and princes, prime ministers and presidents. Viewed from above, a spiral staircase can appear as an ominous eye, an infinite fractal shell or a bottomless work of abstract art. Amazing staircases can be found in incredibly varied forms - including circular, triangular and square - and are made of myriad materials from stone and wood to concrete and metal.
From the Upcoming ueue, submitted by Urbanist.