The basilica of Santa Maria Del Fiore has been for centuries, and remains, one of the top tourist attractions in Florence. It took more than a century and a half to complete, but until modern times, with technological advances in materials, this cathedral had the largest dome ever built. To this day it still has the largest brick constructed dome in the world. One would have to say that there had been quite a feat of engineering that went into producing the octagonal dome.
I've always appreciated how the baptistery emulated the octagonal of the great dome, but Ghiberti's doors grab most of the attention, as well they should. They are truly magnificent. The use of perspective is more than masterful, it's magical considering how shallow the doors really are. I think a trained goldsmith and sculptor was the perfect person to attend to such detail.
While Pisano worked with Ghiberti on the baptistery doors (he made the south facing doors), Donatello was responsible for some of the exterior sculptures. It was Giotto who took over the project who is credited with the campanile (bell tower), although it was Pisano who completed it after Giotto's death. The encroaching city does not give one an optimal vantage point for photographs of Santa Maria Del Fiore, but on each trip I work on a better angle. I plan to enlist the aid of my niece for climbing the dome to take some more photos for me on our upcoming trip. I hope acrophobia doesn't run in the family.