Milan Cathedral, Milan

The Duomo at dusk

Milan Cathedral took more than 600 years to build, and as this dusky shot of Italy's second-biggest city shows, construction work never truly ends. The 21st century has been a time of major restoration for both the interior and—with the assistance of copious scaffolding—the exterior of the Duomo, as it's dearly known by Milan residents. Much of the renovation work has been funded by donations, including a program that allowed locals and businesses (and even enamored tourists) to 'adopt' one of the cathedral's 135 spires.