Commerzbank Tower

This guide to the Commerzbank Tower in Frankfurt opens with the firebombing of March 1944, when incendiary raids burned down the city's medieval old town in a single night. From there it follows Frankfurt's decision, in the 1960s, to rebuild upward instead of small, earning the skyline its Mainhattan nickname, and arrives at architect Norman Foster's 1997 design, with its triangular plan wrapped around a hollow core. Nine sky gardens are cut into that core, framed in steel rather than concrete.