Most of the architecture in Siena treads the line between Gothic and Romanesque styles. The 12th-century Duomo is the most prominent structure, the inside of which is adorned with works of art by Nicola Pisano and Michelangelo. The Piazza del Campo is an important stopover on the sightseeing trail, as it hosts the Palazza Pubblico and its soaring tower. Across the board, St Catherine's Sanctuary pays tribute to the city's favourite saint and mystic. Combination tickets are available for visits to many of these attractions.

Duomo
Siena's 12th-century cathedral is an exceptional example of Romanesque architecture. The standing facade was completed later, in the 14th-century. Inside, visitors can view the octagonal, Gothic pulpit created by Nicola Pisano as well as a set of statues by Michelangelo on one of the altars. Be sure to take in the Pinturicchio frescoes in the Libreria Piccolomini.

Palace of the Archbishop
Sometimes overlooked on the tourist trail, this marvellous building is located near the Siena Duomo. The interior is opulent, laid out with several grand salons and striking works of art. The most notable decoration is the Lorenzetti panel depicting the Madonna del Latte.

Palazzo Salimbeni
One of Siena's most beautiful palaces, the Palazzo Salimbeni is a 14th-century Gothic fortress. Its three-tiered facade is quite impressive and is visible from considerable distance. Inside is one of Italy's oldest banks, the Monte dei Paschi di Siena, locally established in the early 1600s.

Piazza del Campo
The city's most prominent plaza was built across from the Town Hall over the site of the ancient Roman forum. The piazza's unique shell-shape complements the concave shape of the Town Hall facade. Paved in red bricks, the plaza is girded by medieval architecture along with a number of trattorias (informal eateries) and restaurants.

San Domenico Basilica
Built by the Dominican Order in the mid-1100s, this is one of Siena's foremost religious structures. Expansion in the 1300s gave the basilica its Gothic aura. Inside is an enormous nave and a number of tributes to St Catherine, including several paintings depicting scenes from her life. The adjoining chapel of St Catherine houses the saint's only genuine portrait and a portion of her remains.

Sanctuary of St Catherine
The Santuario Cateriniano is a shrine to Siena's most famous saint. Santa Caterina was a mystic from the 1300s who received the marks of the stigmata. Her most famous vision involved her own mystic marriage to the infant Christ and has been a favourite subject for local painters. The sanctuary itself is fronted by an arch with the inscription 'Home of Catherine the Bride of Christ' ('Sponsae Kristi Catherinae Domus').

Torre del Mangia
Standing at a height of 335ft, the 14th-century Torre del Mangia is the bell tower to the town hall building (Palazzo Pubblico). Literally translated, the tower's name means 'Tower for the Eater', referring to the structure's food-loving first guardian. When it was built, the tower was designed to be the same height as the Duomo to acknowledge equality between church and state. Climbing the tower affords a nice view over the city.