Piazza Navona is the shape it is because it follows the outline of a Roman athletics stadium -- the Stadio di Domiziano, built by the Emperor Domitian in 86 AD, was an agon (Greek-style athletics stadium for foot races, discus, and javelin) approximately 275 metres long and 65 metres wide. The curved southern end of the piazza (the rounded terminal that makes Piazza Navona's shape distinctive) corresponds exactly to the curved sphendone of the ancient stadium. The buildings around the piazza were built directly on the ancient stadium substructure; the entire street-level urban form of the area has preserved the 2,000-year-old stadium outline continuously from the ancient period to the present. The underground museum (Museo dello Stadio di Domiziano, accessed from Piazza di Tor Sanguigna, 8 metres below the current ground level) exposes approximately 50 metres of the original first-century AD stadium masonry, with Roman marble decorative elements, athlete inscription fragments, and the specific vaulted passage structure of the ancient building. Rome guide
Plan my Italy trip →Built: 86 AD by Emperor Domitian | Original dimensions: 275 m x 65 m, capacity approximately 30,000 | Museum entry: EUR 7 (Via di Tor Sanguigna 3, Rome) | Open: Daily 10am-6pm | Depth below current ground: 8 metres | The piazza outline: Piazza Navona precisely follows the stadium perimeter
The Stadio di Domiziano was built in 86 AD as a gift to the Roman people from Emperor Domitian -- specifically a Greek-style agon (not a gladiatorial arena but an athletics stadium for the Greek tradition of foot racing, javelin, discus, and wrestling). Domitian was fascinated with Greek culture to the extent that contemporary Romans considered it a character defect; the stadium was one of his most controversial cultural programmes. The stadium's seating capacity was approximately 30,000; it was used regularly for athletics games into the late 4th century. After the end of the Western Roman Empire (476 AD), the stadium was progressively stripped for building material; by the medieval period the stadium floor had become a market space while the surrounding buildings were constructed directly on the ancient seating substructure. The critical urban history: the curved shape of the stadium was too useful as an enclosed public space to abandon -- medieval houses were built in the stadium seats, using the curved stadium perimeter walls as their own exterior walls. The street between the new houses followed the stadium track; the curved southern end was preserved as the curved terminal of the new street. By the 15th century the former stadium track had become the Piazza Navona (from In Agone = Agone = Nagone = Navona, the Italian phonetic corruption of the Greek athletic venue name). The 17th century Baroque transformation (the Bernini fountains -- the Fontana dei Quattro Fiumi, 1651, as the central element) gave the piazza its current character without changing the 2,000-year-old stadium outline.
The Museo dello Stadio di Domiziano (Via di Tor Sanguigna 3, approximately 80 metres north of the Piazza Navona northern entrance, accessible by a staircase descending 8 metres) exposes approximately 50 metres of the original first-century AD stadium structure: the curved ambulatory passage (the vaulted corridor that ran under the stadium seating), sections of the original marble seat supports, fragments of the decorative marble inscription series that identified individual seating sections, and the base level of the stadium arches. The specific experience: looking out from the museum through the excavated gap toward the north, the Piazza Navona buildings are visible above the ancient walls -- the direct vertical relationship between the medieval-Baroque surface city and the Roman substructure is nowhere else in Rome as immediately legible as here. The museum also displays bronze athlete sculpture fragments, a model reconstruction of the original stadium, and the documentary evidence connecting the stadium to the games records of the Agon Capitolinus (the specific games tradition Domitian established). Entry approximately EUR 7. Campidoglio guide
The Stadio di Domiziano is a 1st-century AD Roman athletics stadium built by Emperor Domitian in 86 AD -- a Greek-style agon (foot races, javelin, discus, wrestling) approximately 275 metres long and 65 metres wide with seating for approximately 30,000. The specific significance: the outline of the ancient stadium is precisely preserved in the shape of Piazza Navona, whose buildings were constructed on the ancient seating substructure in the medieval period. The Museo dello Stadio di Domiziano (Via di Tor Sanguigna 3, entry EUR 7) exposes the original 1st-century AD stadium masonry 8 metres below the current ground level.
Piazza Navona's elongated oval shape with the curved southern terminal directly follows the outline of the ancient Stadio di Domiziano (86 AD) -- the medieval and later buildings were constructed directly on the ancient stadium substructure, preserving the 2,000-year-old outline continuously. The piazza name derives from the phonetic corruption of the Latin In Agone (in the Greek athletic venue) through medieval Italian: Agone -- Nagone -- Navona. The curved end of the piazza is the sphendone (the curved terminal of the ancient stadium). This specific urban phenomenon -- the precise imprint of a Roman building on the medieval city plan -- is visible at several Rome locations (the Piazza della Rotonda preserves the Pantheon's circular enclosure; the Via del Portico d'Ottavia preserves the ancient colonnade alignment) but is nowhere as dramatic as the complete stadium outline in Piazza Navona.
The Museo dello Stadio di Domiziano entrance is at Via di Tor Sanguigna 3 -- the street on the northern side of Piazza Navona (the narrow street between the piazza's northern arch and the Palazzo Madama, approximately 80 metres north of the piazza). The museum entrance is not on the piazza itself and is often missed by visitors who do not specifically know to look for it. Open daily 10am-6pm; entry EUR 7. From the Piazza Navona: walk north through the narrow passage on the northwest side of the piazza into the Via di Tor Sanguigna; the museum entrance (a staircase descending to the underground level) is approximately 50 metres along on the left side. Duration: approximately 45-60 minutes for the complete museum visit.
Domitian (Titus Flavius Domitianus, 51-96 AD) was the last Flavian Emperor -- the younger son of Vespasian and younger brother of Titus (who destroyed Jerusalem in 70 AD). He ruled from 81 to 96 AD when he was assassinated by a palace conspiracy. His reputation in Roman and later historical tradition is almost entirely negative: Tacitus, Pliny the Younger, and Suetonius describe him as tyrannical, cruel, and megalomaniacal. Modern scholarship has partially rehabilitated him -- his provincial administration was competent, his building programme substantial (the stadium, the Domus Flavia and Domus Augustana on the Palatine Hill, the Arch of Titus, the Forum of Nerva), and the senatorial hostility that produced the negative literary tradition may reflect class-specific resentment rather than objective assessment. The Roman Senate's damnatio memoriae (formal condemnation of his memory) ordered his name erased from public inscriptions after his murder; the stadium that bears his name survived because the physical structure was too useful to destroy.
Stadio Domiziano Piazza Navona underground + San Clemente three-level church + Domus Aurea Nero palace + Ostia Antica -- the below-ground Rome circuit.
Plan my underground Rome trip →Rome's best underground sites beyond the Stadio di Domiziano: the Basilica di San Clemente (Via di San Giovanni in Laterano -- three levels of Roman history: the current 12th-century church, below it a 4th-century church with extraordinary mosaics, and below that a 1st-century Roman building with a Mithraeum; entry approximately EUR 10, one of the most complete vertical archaeological cross-sections available in Rome); the Domus Aurea (Nero's Golden House, the 1st-century AD imperial palace under the Colle Oppio -- guided tours of the underground excavation, approximately EUR 14; book in advance, the excavation is ongoing); the Palazzo Valentini under the Trajan's Column zone (modern multimedia tour through the Roman patrician house archaeology beneath the Palazzo Valentini, approximately EUR 12); and the Rione Prati area Mithraeum (one of approximately 50 Mithraeums known in Rome -- the Mithraeum of Santa Prisca and the Mithraeum under Santo Stefano Rotondo are occasionally open to visits).
The Fontana dei Quattro Fiumi (Fountain of the Four Rivers, 1651) by Gian Lorenzo Bernini is the central fountain of Piazza Navona -- a pyramidal composition of travertine rock supporting an Egyptian obelisk (the original obelisk from the Circus of Maxentius, originally from Egypt), with four allegorical river figures around the base representing the four great rivers of the four known continents: the Nile (Africa, figure with covered head -- the Nile's source was unknown), the Ganges (Asia, with an oar), the Danube (Europe, with a horse), and the Rio de la Plata (America, with coins). The specific Baroque spatial logic: the massive rocky travertine base appears to float above the water basin, and the obelisk appears to float above the rock -- Bernini's structural engineering (the rock is a hollow shell; the obelisk load is distributed through the rock walls to the foundation) is concealed by the visual mass of the composition. The political programme: the obelisk and the river figures celebrate Pope Innocent X Pamphilj as the ruler of the world's four continents.
Damnatio memoriae (condemnation of memory) was the Roman Senate's formal posthumous punishment for condemned rulers -- the erasure of the condemned person's name from public inscriptions, the destruction of their portraits, and the recycling of their statues. Domitian received a full damnatio memoriae in 96 AD after his assassination; his name was chiselled from building inscriptions throughout Rome, his statues destroyed or recarved as successors, and his public records suppressed. The practical result: many Roman buildings that originally bore Domitian's construction dedication now show Trajan or Nerva (the emperors who succeeded him) as the dedicants; the Arch of Titus (completed by Domitian to honour his brother) does not mention Domitian. The Stadio di Domiziano kept his name in popular tradition despite the damnatio because the physical structure's usefulness outweighed the political need to erase it.
Piazza Navona is the most socially active of Rome's major piazzas -- a 240-metre elongated oval (following the ancient stadium outline) with three Baroque fountains (Bernini's Fontana dei Quattro Fiumi 1651 at the centre; the Fontana del Moro at the south, with a Moor figure by Giacomo della Porta 1575; the Fontana del Nettuno at the north, also della Porta 1575 with the Neptune figure added in the 19th century). The piazza functions as a social gathering space throughout the day and evening; the restaurant perimeter is tourist-priced (best avoided in favour of the streets one block off the piazza for eating); the December Christmas market (mid-December to January 6, the Feast of the Befana) is one of the most traditional Roman seasonal events. The Sant'Agnese in Agone church (1652-1657, by Borromini and Rainaldi) faces Bernini's fountain directly -- the two architectural rivals' works in direct confrontation is the specific Baroque Rome competition visible nowhere else.
Free Roman monuments in Rome: the Pantheon exterior (the interior charges EUR 5 since 2023); the Forum exterior views from the Capitoline Hill Belvedere terrace (the forum interior requires a ticket, but the view from above is free and excellent); the Circo Massimo (the ancient chariot racing venue, the largest in the ancient world, now a public park with the preserved outline and some archaeological remains, free always); the Porta Maggiore (the double-arch monumental gateway where the Aqua Claudia and Aqua Anio Novus entered the city, with the original construction inscription -- free to view from the piazza); the Theater of Marcellus exterior (the semicircular ancient theatre whose arches were incorporated into medieval and Renaissance apartments -- free exterior); and all Roman-era sections of the Appia Antica park (16 km of ancient road flanked by tombs, free always).