The Basilica di Santa Maria del Fiore is the cathedral church of Florence, Italy. I was crazy enough to PAY to walk 463 steps to the top. Once I saw the beautiful view of Florence it was well worth the money and the exhaustion.
Picture of Duomo, Florence, Italy 414 steps on a narrow spiral staircase to the top!
Rooftop of The Duomo - Florence, Italy
Bay of Naples, Naples image gallery - Galleria Umberto I - Lonely Planet