Siena is a city in Tuscany, Italy. It is the capital of the province of Siena. It's distinguished by its medieval brick buildings. The historic center of Siena has been declared by UNESCO a World Heritage Site. It is one of the nation's most visited tourist attractions. Siena is famous for its cuisine, art, museums, medieval cityscape and the Palio, a horse race held twice a year.  The fan-shaped central square, Piazza del Campo, is the site of the Palazzo Pubblico, the Gothic town hall, and Torre del Mangia, a slender 14th-century tower with sweeping views from its distinctive white crown. The city's 17 historic 'contrade' (which are city neighborhoods originally formed as battalions for the city's defense) extend outward from the piazza.

Piazza del Campo is the principal public space of the historic center of Siena, Tuscany, Italy and is regarded as one of Europe's greatest medieval squares. It is renowned worldwide for its beauty and architectural integrity. The Palazzo Pubblico and its Torre del Mangia, as well as various palazzi signorili surround the shell-shaped piazza. At the northwest edge is the Fonte Gaia.  The twice-a-year horse-race, Palio di Siena, is held around the edges of the piazza. The piazza is also the finish of the annual road cycling race Strade Bianche.

The Siena Cathedral (Duomo), begun in the 12th century, is a masterpiece of Italian Romanesque-Gothic architecture. Its main facade was completed in 1380. The original plan called for an ambitiously massive basilica, the largest then in the world, with, as was customary, an east-west nave. However, the scarcity of funds, in part due to war and plague, truncated the project, and the Sienese created a subdued version from the original plan's north-south transept. The east wall of the abandoned original folly of a nave still stands; through an internal staircase, visitors can climb for a grand view of the city.

The Siena Cathedral Pulpit is an octagonal 13th-century masterpiece sculpted by Nicola Pisano with lion pedestals and biblical bas-relief panels. The inlaid marble mosaic floor of the cathedral, designed and labored on by many artists, is among the most elaborate in Italy. The Sacristy and Piccolomini library have well preserved Renaissance frescos by Ghirlandaio and Pinturicchio respectively. Other sculptors active in the church and in the subterranean baptistry are Donatello, Lorenzo Ghiberti, Jacopo della Quercia and others. The Museo dell'Opera del Duomo contains Duccio's famous Maesta (1308-11) and various other works by Sienese masters. More Sienese paintings are to be found in the Pinacoteca, e.g. 13th-century works by Dietisalvi di Speme.

The Piazza del Campo, the shell-shaped town square, unfurls before the Palazzo Pubblico with its tall Torre del Mangia. This is part of the site for the Palio horse race. The Palazzo Pubblico, itself a great work of architecture, houses yet another important art museum. Included within the museum is Ambrogio Lorenzetti's frescoes depicting the Allegory and Effects of Good and Bad Government and also some of the finest frescoes of Simone Martini and Pietro Lorenzetti.

The Palazzo Salimbeni, located in a piazza of the same name, was the original headquarters and remains in possession of the Monte dei Paschi di Siena, one of the oldest banks in continuous existence in Europe.

Housed in the notable Gothic Palazzo Chigi-Saracini is the Accademia Musicale Chigiana, Siena's conservatory of music.  Over the centuries, Siena has had a rich tradition of arts and artists. The list of artists from the Sienese School include Duccio and his student Simone Martini, Pietro Lorenzetti and Martino di Bartolomeo. A number of well-known works of Renaissance and High Renaissance art still remain in galleries or churches in Siena.  The Church of San Domenico contains art by Guido da Siena, dating to the mid-13th century. Duccio's Maesta, which was commissioned by the City of Siena in 1308, was instrumental in leading Italian painting away from the hieratic representations of Byzantine art and directing it towards more direct presentations of reality. And his Madonna and Child with Saints polyptych, painted between 1311 and 1318, remains at the city's Pinacoteca Nazionale.

Other churches in the city include:

Basilica dell'Osservanza
Santa Maria dei Servi
San Francesco
Santo Spirito
San Martino
Sanctuary of Santa Caterina, incorporating the old house of St. Catherine of Siena. It houses the miraculous Crucifix (late 12th century) from which the saint received her stigmata, and a 15th-century statue of St. Catherine.
The historic Siena synagogue is also preserved and open to visitors.

The city's gardens include the Orto Botanico dell'Universita di Siena, a botanical garden maintained by the University of Siena.  The Medicean Fortress houses the Enoteca Italiana and the Siena Jazz School, with courses and concerts throughout the year, and a festival during the International Siena Jazz Masterclasses. In the neighborhood are numerous patrician villas, some of which are attributed to Baldassarre Peruzzi.

Siena retains a ward-centric culture from medieval times. Each ward (contrada) is represented by an animal or mascot, and has its own boundary and distinct identity. Ward rivalries are most rampant during the annual horse race in the Piazza del Campo.

The Palio di Siena as previously mentioned is a traditional medieval horse race run around the Piazza del Campo twice each year, on 2 July and 16 August. The event is attended by large crowds, and is widely televised. Seventeen Contrade vie for the trophy: a painted banner, or Palio bearing an image of the Blessed Virgin Mary.