Orvieto Cathedral so dominates the town that it's spectacular size almost overwhelms the main piazza.
The Cathedral saw a succession of celebrated artists and architects, such as Lorenzo Maitani, Andrea Pisano, and Orcagna,
who worked as Capomasters beginning in 1290. Construction continued for several centuries.
The Cathedral's exterior is dominated by the green and white particolore marbles, a style popular in Tuscany at the time.
This style can also be seen in the Duomo in Florence and in Siena Cathedral.

The Cathedral,is associated with the "Miracle of Bolsena" in 1263, which is celebrated as the Feast of Corpus Christi.
This miracle occurred when a Priest broke the communion wafer and it "bled" on the altar cloth, symbolizing Christ's blood shed for the faithful.
This holy relic is preserved in a silver reliquary in Orvieto Cathedral, and taken yearly on on a pilgrimage to the neighboring town of Bolsena ,
where it is celebrated in a great parade and venerated in the Cathedral there.

In the right transept of Orvieto Cathedral is the Brizio Chapel which contains celebrated frescoes begun by Fra Angelico,
who painted the ceiling vaults over the altar, but died before they were completed.
Luca Signorelii from Cortona completed the work, and painted the most famous fresco in the chapel, "The Last Judgement" on the right wall .
Signorelli's fresco, showing the dead climbing out of their tombs, is known to have influenced Michelangelo's "Last Judgemetnt" in the Sistine Chapel.
In the upper left corner of the Brizio Chapel, there are two figures in black, portraits of Fra Angelico and Signorelli.

No photos are allowed in the Brizio Chapel, but pictures of the frescoes can be found online.