An oval baroque square built inside a Roman stadium
This point sits inside Piazza Navona, a long oval square in central Rome shaped exactly like the stadium buried underneath it.
Last reviewed 4 October 2026 · A three-minute read · 1219 BC–2014
The short answer
Piazza Navona in Rome traces the exact oval outline of the Stadium of Domitian, a 30,000-seat arena built around AD 80. Games were held there until 407 AD, after which the ruins became housing and later a market. The square now holds Bernini's Four Rivers Fountain, and the buried stadium beneath it opened to visitors in 2014.
Grillo a Piazza Navona 15/03/08 - Lista Civica — 2008 · Yellow.Cat from Roma, Italy · CC BY 2.0
86 AD to 1500s
A stadium for 30,000 became a market square
Piazza Navona is a public square in Rome, paved in stone and lined with cafés and street artists. Its long, rounded shape is not an accident of city planning. It is the exact outline of the Stadium of Domitian, a stadium the emperor Domitian built around 80 AD as a gift to the Roman people. Romans came here to watch footraces, wrestling, and boxing, games they called the agones. Some say the square's name grew out of that word, drifting from "in agone" to "navona" over centuries.
The stadium could hold about 30,000 people. Fire damaged it under Emperor Macrinus, and it was repaired again under Alexander Severus. The last recorded games were held here in 407 AD. After Rome's empire collapsed, people moved into the stadium's old walls and arches, turning the ruins into cramped housing. By the 1400s, the hollow of the old arena had become one of the city's main open-air markets, and its buried curve was paved over to make the square people walk across today.
Piazza Navona's ground held darker moments. Christian tradition says a young girl named Agnes of Rome was stripped and killed here in 304 AD, during the persecution of Diocletian. A church, Sant'Agnese in Agone, later rose on the spot to mark it. In 1556, during the Roman Inquisition, a 24-year-old student named Pomponio Algerio was executed here for Lutheran heresy. Pomponio Algerio was boiled alive in oil and reportedly stayed calm through roughly fifteen minutes of dying.
1644 to 1651
A pope and a rival's model decided the fountain
Pope Innocent X Pamphilj took charge of the square in the mid-1600s. Innocent X's family palace, Palazzo Pamphilj, faced onto it, and Innocent X wanted a stage worthy of his name. He commissioned the church of Sant'Agnese in Agone on the site tied to Agnes's death, and he wanted a grand fountain to stand in front of it.
Innocent X first leaned toward Francesco Borromini for the fountain design. Gian Lorenzo Bernini was out of favor at the papal court at the time. A story holds that Bernini's friend, Prince Niccolò Ludovisi, placed a silver model of the fountain where the pope would see it inside Palazzo Pamphilj. The pope reportedly changed his mind on the spot and gave Bernini the job.
Around the same time, Innocent X visited the church of Saint Sebastian and found a broken Egyptian obelisk lying along the Appian Way. Innocent X had it brought to the square for the fountain's crown.
Between 1648 and 1651, Bernini built the Fountain of the Four Rivers. Four marble figures represent the Nile, Ganges, Danube, and Rio de la Plata, gathered around a travertine rock holding up the obelisk. Bernini topped the obelisk with a dove and an olive branch, the Pamphilj family's emblem, wings spread as if about to fly.
A popular story claims Bernini angled one of the river figures with a hand raised, bracing against the dome of Sant'Agnese next door, a jab at Borromini, who designed that church. The timeline makes this unlikely. Bernini's fountain stood finished years before Borromini began work on the church at all.
1651 to 1800s
The square was flooded into a lake each summer
For well over a century after the fountain went up, the square doubled as a place to cool off. Workers closed the fountain drains on summer days and let the water rise, flooding the piazza into a shallow lake. Romans waded through it until sometime after 1800, when the custom ended.
1936 to 2014
Demolition revealed the stadium still buried below
In 1936, houses that had stood on the square for generations were torn down as part of a wider effort to modernize the area. Excavators later found that the Stadium of Domitian still lay beneath the piazza, buried about fifteen feet down, its curved walls intact.
In 2014, those underground remains opened to the public for the first time. Visitors can now walk through the old stadium passages with an audio guide, standing among the brick and travertine that Domitian's builders laid nearly two thousand years earlier.
Piazza Navona today is a plaza of cafés, street painters, and three fountains, laid out in the exact oval of a Roman stadium buried a few feet below the stones.
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Prehistoric
1219 BC - 1015 BC
Samples from the Sant'Omobono excavation, about 1.1 kilometers from here, carry radiocarbon dates stretching from 1219 BC, showing people working this stretch of the Tiber valley centuries before Rome's founding legends.
The tomb of Aulus Hirtius, consul in 43 BC, once stood in the Campus Martius a short walk from here, back when this ground was still open field outside the city walls.
In 1556 Pomponio Algerio, a Lutheran student, was executed by boiling in oil for heresy during the Roman Inquisition and reportedly kept his composure for over an hour.
From 1644 Pope Innocent X Pamphilj commissioned the Palazzo Pamphilj, the church of Sant'Agnese in Agone, and the Four Rivers Fountain to showcase his family here.
Bernini secretly built a silver model of his fountain design and had it placed where the pope would see it, winning him the commission over his rival Borromini.
Innocent X found the Egyptian obelisk lying in pieces near the church of Saint Sebastian and had it reassembled from five sections atop Bernini's fountain.
From 1652 until 1866 the drains were closed every August weekend so the piazza filled with water, a Pamphilj family celebration that lasted over 200 years.
In the early hours of 3 September 2011 a man climbed into the Fontana del Moro and smashed the heads off several figures before being identified by his shoes on security footage.
The ancient arena, sitting about 4.5 meters below the paving, opened to the public in 2014 with excavated walls and arches you can now walk beneath the square to see.
The Stadium of Domitian stood here, built around AD 80 as a 30,000-seat arena for footraces, wrestling, and boxing. After the empire collapsed, people moved into its ruined arches, and by the 1400s the hollow arena had become an open-air market.
Why is Piazza Navona oval shaped?
The square's long, rounded shape is the exact outline of the Stadium of Domitian's old racetrack, buried beneath the paving that covers it today.
What happened at Piazza Navona in 1556?
A 24-year-old Lutheran student named Pomponio Algerio was executed by being boiled alive in oil during the Roman Inquisition, and he reportedly kept his composure through the ordeal.
Who designed the Four Rivers Fountain in Piazza Navona?
Gian Lorenzo Bernini designed it, reportedly winning the commission after his friend placed a silver model of the fountain where Pope Innocent X would see it inside Palazzo Pamphilj, despite the pope's earlier favour toward Bernini's rival Borromini.
What is buried beneath Piazza Navona?
The walls, pillars and stairs of the ancient Stadium of Domitian lie beneath the square, about fifteen feet down, and have been open to the public to walk through since 2014.
Did Piazza Navona ever flood on purpose?
From 1652 until 1866, the fountain drains were closed on summer weekends so the piazza filled with water, a Pamphilj family tradition that lasted over two centuries.
