Cathedral of Santa Maria del Fiore in Florence, the Duomo.

The cathedral was begun at the end of the 13th century by di Cambio, and the dome, which dominates the exterior in Filippo Brunelleschi.

A statue to each of these important architects can be found outside to the right of the cathedral, both admiring their work for the rest of eternity. Can you imagine it took two centuries for the cathedral to be deemed finished???

The exterior is covered in a decorative mix of pink, white and green marble. The interior, by contrast, is pretty stark and plain but quite enjoyable on warm summer days since the temperature inside tends to be cooler. The mosaic pavements are certainly its main attraction within.