One of the main attractions in the hilltop town of Orvieto is the its cathedral, or Duomo. Construction began in 1290, but the cathedral wasn't complete until more than 300 years later, and today, the often-photographed facade is covered in artwork, from gold mosaics to multi-colored marble to carvings and bronze doors.
Inside the cathedral is more striped marble, though the ceiling is made of wood. Much of the interior dates from the 14th century, including the wooden choir stalls and stained glass windows. There are wonderful Signorelli frescoes in the Chapel of the Madonna di San Brizio.
The cathedral is open November-February from 7:30am-1pm and 2:30-5pm, March and October from 7:30am-6pm, and April-September from 7:30am-7pm. Admission is €3 for the Duomo, or €5 for a combined ticket including the Duomo, Treasury, and museum.