The Piazza dei Miracoli, also called Piazza del Duomo, is an enclosed area covering 8.87 hectares (21.9 acres) in central Pisa, Tuscany, Italy. It is known as an important place for European medieval art and one of the world's finest architectural groups. The area was owned by the Catholic Church and includes four major religious buildings: Pisa Cathedral, the Pisa Baptistery, the Leaning Tower of Pisa (the cathedral's bell tower), and the Camposanto Monumentale (Monumental Cemetery). The square has both paved and grassy areas and also includes the Ospedale Nuovo di Santo Spirito (New Hospital of the Holy Spirit), which now holds the Sinopias Museum and the Cathedral Museum.

The square's name, "Piazza dei Miracoli," was given by Italian writer and poet Gabriele D'Annunzio in his novel Forse che sì forse che no (1910), where he called it the "prato dei Miracoli," or "meadow of miracles." It is sometimes also called the "Campo dei Miracoli" ("Field of Miracles"). In 1987, the entire square was named a UNESCO World Heritage Site.

Cathedral

The Piazza del Duomo is mainly shaped by Pisa Cathedral, also called the Duomo. This medieval church belongs to the Archdiocese of Pisa and is dedicated to Santa Maria Assunta, or Saint Mary of the Assumption. The cathedral has two aisles on each side of the main aisle. The transept, which crosses the main part of the church, has three aisles. The church is also called the Primatial because the bishop of Pisa became a Primate in 1092.

Construction of the cathedral began in 1064, designed by the architect Buscheto. This design influenced the Pisan Romanesque style of architecture. The interior has mosaics and pointed arches, showing the influence of the Byzantine Empire.

The front of the cathedral is made of grey marble and white stone, with colored marble discs. A master named Rainaldo built it, as noted by an inscription above the middle door: "Rainaldus prudens operator."

The large bronze main doors were made by Giambologna’s workshop, replacing the original doors destroyed in a fire in 1595. The original central door was made of bronze by Bonanno Pisano around 1180, while the other two were likely wooden. However, worshippers have never used the front doors to enter. Instead, they used the Porta di San Ranieri, near the Leaning Tower, also built by Bonanno Pisano around 1180.

Above the doors are four rows of open galleries. On top, there are statues of the Madonna with Child, and on the corners, the Four Evangelists. The façade also includes the tomb of Buscheto on the left side and an inscription about the cathedral’s founding and a battle against the Saracens.

At the east end of the exterior, high on a column, is a modern copy of the Pisa Griffin. This is the largest known Islamic metal sculpture. The original was placed there in the 11th or 12th century and is now in the Cathedral Museum.

The interior is covered in black and white marble, with a gilded ceiling and a frescoed dome. After the 1595 fire, most Renaissance artworks were destroyed, and the interior was redecorated.

A large mosaic of Christ in Majesty, flanked by the Virgin and Saint John the Evangelist, survived the fire. This mosaic is similar to those in the church of Monreale, Sicily. It is said that Cimabue created the mosaic, but only the head of Saint John was his work in 1302, his final piece before he died in Pisa that year. The cupola, where the nave and transept meet, was decorated by Riminaldi, showing the Assumption of the Virgin.

Galileo is believed to have studied the movement of a pendulum by watching an incense lamp swing in the nave. The original lamp, smaller and simpler than the current one, is now in the Camposanto’s Aulla chapel.

The granite Corinthian columns between the nave and aisle originally came from the mosque of Palermo, captured by the Pisans in 1063.

The coffered ceiling of the nave was replaced after the 1595 fire. The current gold-decorated ceiling displays the Medici family’s coat of arms.

The pulpit, carved between 1302 and 1310 by Giovanni Pisano, survived the fire. It was rediscovered and restored in 1926 after being stored during redecoration. The pulpit is supported by plain columns and caryatids, with statues representing Saint Michael, the Evangelists, the four cardinal virtues, and a naturalistic depiction of Hercules. A central plinth holds the liberal arts, supporting the four theological virtues. The original pulpit’s position near the main altar was changed, and some parts were lost. The upper part has nine scenes from the New Testament, carved in white marble with light and dark areas, separated by prophets.

The cathedral also holds the bones of Saint Ranieri, Pisa’s patron saint, and the tomb of Holy Roman Emperor Henry VII, carved by Tino da Camaino in 1315. The tomb was moved many times due to political reasons. Some statues are now in the Camposanto or on the cathedral’s façade, while the original pieces are in the Museo dell'Opera del Duomo. Pope Gregory VIII was also buried in the cathedral, but his tomb was destroyed in the 1595 fire.

The cathedral marks the start of the Pisan New Year. From the 10th century to 1749, Pisa used its own calendar, with the year beginning on March 25, the feast day of the Annunciation. A ray of sunlight through a window on the left side falls on an egg-shaped marble near the pulpit at noon, signaling the start of the year.

Relics from the Crusades, including remains of three saints and a jar from Cana, are also in the cathedral.

The building, like others in Pisa, has slightly tilted since construction, though not as much as the nearby Leaning Tower.

Features include:
– Lunette above the central door by Giuseppe Modena da Lucca, showing the Virgin Mary
– Apse with mosaic
– Coffered ceiling
– Altar of Saint Rainerius
– Interior view of the central part
– Marble columns
– The Compound, with the Pisa Griffin above the apse on a column
– Aerial view of Piazza del Duomo
– The Leaning Tower with the Duomo and Baptistery at night
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Baptistery

The Baptistery, named after St. John the Baptist, is located across from the west side of the Duomo. This round Romanesque building started construction in the middle of the 12th century. A Latin inscription on the structure reads, "In the month of August 1153 was set up here…" The building was designed in the Romanesque style by an architect named Diotisalvi, which means "God Save You." He also worked on the church of the Holy Sepulchre in the city. His name appears on a pillar inside the Baptistery as "Diotosalvi magister." Construction was not completed until the 14th century, when the loggia, top floor, and dome were added in the Gothic style by Nicola Pisano and his son, Giovanni Pisano.

The Baptistery is the largest in Italy, with a circular shape measuring 107.25 meters around. Including the statue of St. John the Baptist (created by Turino di Sano) on top of the dome, it is slightly taller than the Leaning Tower.

The entrance, which faces the cathedral’s façade, has two classical columns on either side. Inside, the door frames are decorated in the Byzantine style. The lintel above the entrance has two sections: the lower part shows scenes from the life of St. John the Baptist, and the upper part shows Christ between the Madonna and St. John the Baptist, surrounded by angels and the four evangelists.

The inside of the Baptistery is very large and feels surprising simple, with few decorations. It also has excellent acoustics, meaning sound carries clearly.

At the center of the building is an octagonal baptismal font built in 1246 by Guido Bigarelli da Como. A bronze statue of St. John the Baptist, placed in the center of the font, was created by Italo Griselli.

A famous pulpit, made between 1255 and 1260 by Nicola Pisano, is located inside. Nicola Pisano was the father of Giovanni Pisano, who later created a pulpit in the Duomo. The scenes on the pulpit, especially the image of Hercules, show Nicola Pisano’s skill in reviving ancient artistic styles. Because of this, many studies of the Italian Renaissance begin with the year 1260, the year Nicola Pisano marked on the pulpit.

• Baptistry dome
• Baptistry interior
• Baptistry font by Guido Bigarelli da Como
• Pulpit by Nicola Pisano
• Stained-glass window
• Baptistery floor

Campanile

The campanile, also known as the Leaning Tower of Pisa, is located behind the cathedral. It was the last of the three main buildings on the piazza to be built. Construction of the bell tower began in 1173 and took 177 years, with three stages of building. The bell-chamber was added in 1372. Five years after construction started, when the building reached the third floor, weak ground and poor foundations caused it to sink on the south side. The building was not used for a century, which allowed the ground to become stable and prevented it from collapsing. In 1272, to fix the lean, when construction resumed, the upper floors were built with one side taller than the other. The seventh and final floor was added in 1319. When the building was finished, the lean was about 1 degree, or 80 cm (2.5 feet) from vertical. At its greatest, measured before 1990, the lean was about 5.5 degrees. By 2010, the lean had been reduced to about 4 degrees.

The tower is about 60 meters high and was built to hold seven main bells, made in a musical order:

• L'Assunta, made in 1654 by Giovanni Pietro Orlandi, weighs 3,620 kg (7,981 lb)
• Il Crocifisso, made in 1572 by Vincenzo Possenti, weighs 2,462 kg (5,428 lb)
• San Ranieri, made in 1719–21 by Giovanni Andrea Moreni, weighs 1,448 kg (3,192 lb)
• La Terza, the first small bell, made in 1473, weighs 300 kg (661 lb)
• La Pasquereccia or La Giustizia, made in 1262 by Lotteringo, weighs 1,014 kg (2,235 lb)
• Il Vespruccio, the second small bell, made in the 14th century and again in 1501 by Nicola di Jacopo, weighs 1,000 kg (2,205 lb)
• Dal Pozzo, made in 1606 and again in 2004, weighs 652 kg (1,437 lb)

There are 296 steps leading to the top of the tower.

Camposanto Monumentale

The Camposanto Monumentale, also called Campo Santo or Camposanto Vecchio, is located at the northern edge of the square. This walled cemetery was built around sacred soil from Calvary, brought to Pisa by Ubaldo de' Lanfranchi, the archbishop of Pisa in the 12th century. This is where the name Campo Santo, meaning "Holy Field," comes from.

The building was constructed about a century later over the earlier burial ground. The large, long Gothic-style structure began in 1278 by the architect Giovanni di Simone. He died in 1284 during a naval battle with the Genoans near Meloria. The cemetery was completed in 1464. The outer wall has 43 arches without openings. There are two doorways. The one on the right has a Gothic-style tabernacle with a statue of the Virgin Mary and Child surrounded by four saints. This artwork was made in the second half of the 14th century by a follower of Giovanni Pisano. Most tombs are under the arcades, while a few are on the central lawn. The inner court has round arches with thin vertical supports and intricate window designs.

The Camposanto Monumentale once held many Roman sculptures and sarcophagi, but only 84 remain today. The walls were once covered in paintings. The first paintings were added in 1360, and the last were added about three centuries later. The north gallery had stories from the Old Testament by Benozzo Gozzoli, while the south arcade had stories from Genesis by Piero di Puccio. The most famous painting is The Triumph of Death, created by Buonamico Buffalmacco. On July 27, 1944, bombs from Allied planes caused the roof to catch fire and melted lead covering the paintings, nearly destroying them. Since 1945, restoration work has been done to return the Campo Santo to its original condition.

• Camposanto Monumentale interior
• Hall

Ospedale Nuovo di Santo Spirito

The Ospedale Nuovo di Santo Spirito (New Hospital of Holy Spirit) is located on the southern part of the square. It was built in 1257 by Giovanni di Simone over a smaller hospital that was already there. The hospital’s purpose was to help people who were sick, poor, or had no family by offering them shelter. Later, the hospital was renamed Ospedale della Misericordia (Hospital of Mercy) or Ospedale di Santa Chiara (Hospital of Saint Clare), named after the small church that was part of the building.

The hospital’s outside walls were made of brick and had two-light windows in the Gothic style. Inside, the walls were painted black and white to look like marble, which was used in other buildings nearby. In 1562, during the time when the Medici family ruled the city, the hospital was rebuilt using Renaissance design standards. All the doors and windows were changed to new rectangular ones made of grey sandstone.

Today, the building is not used as a hospital anymore. Since 1976, the middle section of the building has been turned into the Sinopias Museum, which houses original drawings of frescoes from the Campo Santo.

Palazzo dell'Opera

The Palazzo dell'Opera, named for the "works" or workshops of the complex, is located at the southeast corner of the square. Different parts of the building were constructed during various time periods, with the main structure dating back to at least the 14th century and the most recent additions built in the 19th century.

Originally, these buildings belonged to workers connected to the cathedral, such as tailors, gardeners, and bell ringers. In the 19th century, the administration offices of the Opera della Primaziale moved into the complex, and the chapter house was also relocated there. Over time, the layout of the complex was changed several times, but the front of the main building still looks the same as it did originally.

In the early 2000s, the administration offices and chapter moved to a nearby palace near the archbishopric. Only a few rooms on the ground floor are now used for offices related to security and technical staff. After the move, the upper rooms were converted into a space for temporary art exhibitions, starting in 2014. This was the first time these rooms were open to the public.

The most accessible rooms for visitors include the President room, the Deputation room, the chapel, and the Chapter room. Some rooms remain closed to the public, such as the "Loggetta" room, which has frescoes by Agostino Ghirlanda, and the "Scrittoio" room, which contains a fresco by Il Sodoma. Other closed rooms include the "Viola" room and the technical room.

Key features include:
– The main entrance
– The corridor on the ground floor
– A fresco in the technical room, painted in the early 15th century by a Sienese artist
– A fresco in the Deputation room, painted in 1299 by Vincino di Vanni and Giovanni d'Apparecchiato
– Original parts of Giovanni Pisano’s pulpit in the President room
– The Pisa Griffin in the Chapter room
– The chapel