Siena Cathedral, or Duomo di Siena, is a medieval church in Siena, Italy, that stands as a masterful example of Italian Romanesque-Gothic architecture. Begun in the 12th century and completed in the 13th, it is famous for its exquisite façade adorned with marble and sculptures. The cathedral's imposing bell tower and its unique striped pattern of black and white marble symbolize the colors of Siena and the emblem of the city. Inside, visitors are greeted by a wealth of artistry including a remarkable mosaic floor depicting biblical stories and historical events, which is covered and unveiled at certain times of the year for preservation. The Piccolomini Library with frescoes by Pinturicchio, adorned with vibrant colors and gold, and the octagonal pulpit carved by Nicola Pisano add to the cathedral's rich interior. The structure also features works by Donatello and Michelangelo and houses important relics and art pieces. Exploring Siena Cathedral is not just a religious experience but also a journey through art, history, and architecture.