Since 2005, the entire city of Syracuse, along with the Necropolis of Pantalica which falls within the province of Syracuse, were listed as a World Heritage Site by UNESCO. This programme aims to catalogue, name and conserve sites of outstanding cultural or natural importance to the common heritage of humanity. The deciding committee which evaluates potential candidates described their reasons for choosing Syracuse because "monuments and archeological sites situated in Syracuse are the finest example of outstanding architectural creation spanning several cultural aspects; Greek, Roman and Baroque", following on that Ancient Syracuse was "directly linked to events, ideas and literary works of outstanding universal significance".

Sights include:

• The Temple of Apollo, at Piazza Emanuele Pancali, adapted to a church in Byzantine times and to a mosque under Arab rule.
• The Fountain of Arethusa, on the Ortygia island. According to a legend, the nymph Arethusa, hunted by Alpheus, took shelter here.
• The Greek Theatre, whose cavea is one of the largest ever built by the ancient Greeks: it has 67 rows, divided into nine sections with eight aisles. Only traces of the scene and the orchestra remain. The edifice (still used today) was modified by the Romans, who adapted it to their different style of spectacles, including also circus games. Near the theatre are the latomìe, stone quarries, also used as prisons in ancient times. The most famous latomìa is the Orecchio di Dionisio ("Ear of Dionysius").
• The Roman amphitheatre. It was partly carved out from the rock. In the centre of the area is a rectangular space which was used for the scenic machinery.
• The Tomb of Archimede, in the Grotticelli Nechropolis. Decorated with two Doric columns.
• The Temple of Olympian Zeus, about 3 kilometres (2 miles) outside the city, built around 6th century BC.
• The Cathedral of Syracuse (Italian: Duomo) was built by bishop Zosimo in the 7th century over the great Temple of Athena (5th century BC), on Ortygia island. This was a Doric edifice with six columns on the short sides and 14 on the long sides: these can still be seen incorporated in the walls of the current church. The base of the temple had three steps. The interior of the church has a nave and two aisles. The roof of the nave is from Norman times, as well as the mosaics in the apses. The façade was rebuilt by Andrea Palma in 1725-1753, with a double order of Corinthian columns, and statues by Ignazio Marabitti. The most interesting pieces of the interior are a font with marble basin (12th-13th century), a silver statue of St. Lucy by Pietro Rizzo (1599), a ciborium by Luigi Vanvitelli, and a statue of the Madonna della Neve ("Madonna of the Snow", 1512) by Antonello Gagini.
• Basilica of Santa Lucia Extra moenia, a Byzantine church built (after Norman rebuilt), according to tradition, in the same place of the martyrdom of the saint in 303 AD. The current appearance is from the 15th-16th centuries. The most ancient parts still preserved include the portal, the three half-circular apses and the first two orders of the belfry. Under the church are the Catacombs of St. Lucy. For this church Caravaggio painted the Burial of St. Lucy, now housed in the Church of Santa Lucìa alla Badìa.
• Our Lady of Tears Shrine (20th century).
• Church of San Filippo Apostolo with downstair his Jewish Mikvah (18th century).
• Church of San Paolo (18th century).
• Church of San Cristoforo (14th century, rebuilt in the 18th century).
• Church of Santa Lucìa alla Badìa, a Baroque edifice built after the 1693 earthquake. It houses the Burial of St. Lucy by Caravaggio
• Church of San Giovanni Battista (14th century).
• Church of Santa Maria dei Miracoli (14th century).
• Church of the Spirito Santo (18th century).
• Church of the Jesuit College, a majestic, Baroque building.
• Church of St. Benedict (16th century, restored after 1693). It houses a painting of the Death of Saint Benedict by the Caravaggisti Mario Minniti.
• Chiesa della Concezione (14th century, rebuilt in the 18th century), with the annexed Benedictine convent.
• Church of San Francesco all'Immacolata, with a convex façade intermingled by columns and pilaster strips. It housed and ancient celebration, the Svelata ("Revelation"), in which an image of the Madonna was unveiled at dawn of 29 November.
• Basilica of St. John the Evangelist, built by the Normans and destroyed in 1693. Only partially restored, it was erected over an ancient crypt of the martyr San Marciano, later destroyed by the Arabs. The main altar is Byzantine. It includes the Catacombs of San Giovanni, featuring a maze of tunnels and passages, with thousands of tombs and several frescoes.
• Castello Maniace, constructed between 1232 and 1240, is an example of the military architecture of Frederick II's reign. It is a square structure with circular towers at each of the four corners. The most striking feature is the pointed portal, decorated with polychrome marbles.
• The important Archaeological Museum, with collections including findings from the mid-Bronze Age to 5th century BC.
• Palazzo Lanza Buccheri (16th century).
• Palazzo Bellomo (12th century), which contains an art museum that houses Antonello da Messina's Annunciation (1474).
• Palazzo Montalto (14th century), which conserves the old façade from the 14th century, with a pointed portal.
• The Archbishop's Palace (17th century, modified in the following century). It houses the Alagonian Library, founded in the late 18th century.
• The Palazzo Vermexio, the current Town Hall, which includes fragments of an Ionic temple of the 5th century BC.
• Palazzo Francica Nava, with parts of the original 16th century building surviving.
• Palazzo Beneventano del Bosco, originally built in the Middle Ages but extensively modified between 1779 and 1788. It has a pleasant internal court.
• Palazzo Migliaccio (15th century), with notable lava inlay decorations.
• The Senate Palace, housing in the court an 18th-century coach.
• The Castle of Euryalos, built 9 kilometres (6 miles) outside the city by Dionysius the Elder and which was one of the most powerful fortresses of ancient times. It had three moats with a series of underground galleries which allowed the defenders to remove the materials the attackers could use to fill them.
• The Mikveh: a bath used for the purpose of ritual immersion in Judaism, built during the Byzantine era. It is situated in the Giudecca: the ancient Jewish Ghetto of Syracuse.