Province of Italia · Founded ~350 BCE (castrum)

Rome's port at the mouth of the Tiber, at its commercial peak under Trajan.

Today: An uninhabited archaeological park near Rome's Fiumicino airport; no modern town overlies it, so the ancient street grid, warehouses, and theatre are fully walkable.

Province of Italia · Founded 6th c. BCE (Oscan)

Buried 79 CE by Vesuvius. Frozen at that moment — houses, shops, graffiti and all.

Today: An uninhabited, fully excavated UNESCO World Heritage site and one of Italy's most-visited attractions, still yielding new discoveries from the 79 CE eruption.

Province of Italia · Founded 6th c. BCE

Coastal resort town buried by Vesuvius. Wood, papyri, and food survived under 20m of pyroclastic mud.

Today: Only partly excavated; the modern town of Ercolano sits atop much of the unexcavated remains, UNESCO-listed jointly with Pompeii.

Province of Asia · Founded 10th c. BCE (Ionian)

Capital of the province of Asia, home of the Temple of Artemis (one of the Seven Wonders) and the Library of Celsus.

Today: An uninhabited UNESCO World Heritage archaeological site by the town of Selcuk, Turkey, one of the best-preserved ancient cities in the Mediterranean.

Province of Numidia · Founded 100 CE by Trajan

A veterans' colony founded by Trajan for Legio III Augusta. A textbook Roman grid, 17 years old at our snapshot.

Today: Uninhabited since a 7th-century Arab invasion; now a fully excavated, empty UNESCO World Heritage archaeological park in the Aures Mountains near Batna, Algeria.

Province of Numidia · Founded 96 CE by Nerva

Mountain colony of veterans (Roman Cuicul), contemporary with Timgad. Its stepped forum climbs the hillside.

Today: Uninhabited UNESCO World Heritage Roman ruins on a mountain plateau, prized for their mosaics, near a small namesake village in northern Algeria.

Province of Mauretania Tingitana · Founded 3rd c. BCE (Berber)

Frontier city at the edge of the empire, only recently annexed (44 CE). Olive-oil boom town.

Today: An uninhabited UNESCO World Heritage site near Meknes, Morocco; abandoned in the 11th century, its stones later quarried to help build Meknes.

Province of Africa Proconsularis · Founded 1000 BCE (Phoenician)

Phoenician foundation, later home of emperor Septimius Severus. Its 2nd-century monumental core was still being planned in 117 CE.

Today: An uninhabited UNESCO World Heritage site on Libya's coast, well preserved, and reopening to visitors as Libya's tourism slowly recovers.

Province of Africa Proconsularis · Founded 5th c. BCE

One of the three cities of Tripolitania. Its theatre is one of the largest surviving anywhere in North Africa.

Today: An uninhabited UNESCO World Heritage site on Libya's coast, placed on UNESCO's List of World Heritage in Danger in 2016 due to conflict-related damage and neglect.

Province of Arabia Petraea · Founded 170 BCE (Seleucid)

Best-preserved of the Decapolis cities (Roman Gerasa). Oval forum, colonnaded cardo, Temple of Artemis.

Today: A living Jordanian city of around 50,000 whose homes sit alongside ancient Gerasa's ruins, one of the best-preserved Greco-Roman cities outside Italy.

Province of Syria · Founded 1st c. BCE (Aramean)

Caravan city on the trade route between Rome and the Silk Road. Great colonnaded street, Temple of Bel.

Today: Uninhabited and badly damaged by ISIS occupation from 2015 to 2017, which destroyed the Temple of Bel, the Baalshamin temple, and the Arch of Triumph; restoration efforts continue.

Province of Syria · Founded 1st c. BCE (Roman colony)

Roman Heliopolis. Temple of Jupiter — one of the largest sanctuaries in the empire. Still under construction in Trajan's day.

Today: A living Lebanese city of roughly 80,000 in the Bekaa Valley; its UNESCO-listed Roman temples of Jupiter and Bacchus stand within the modern town.

Province of Italia · Founded 753 BCE (traditional)

Caput mundi. Around 1 million people in 117 CE — the largest city on earth for centuries either side.

Today: Italy's capital of nearly 3 million people; the Colosseum, Forum, and Palatine form a fenced, uninhabited archaeological park inside the UNESCO-listed historic centre.

Province of Pannonia · Founded 89 CE (legionary fortress)

Base of Legio II Adiutrix on the Danube frontier. The proconsul Hadrian lived here just before becoming emperor in 117.

Today: Buried beneath modern Budapest's Obuda district; an open-air ruin garden and museum preserve excavated sections within the living city.

Province of Pannonia · Founded 40 CE

Major Danube legionary base and the civilian city that grew beside it. Marcus Aurelius later wrote parts of the Meditations here.

Today: An uninhabited archaeological park and open-air museum near Petronell-Carnuntum, Austria, with reconstructed Roman houses, part of the UNESCO Danube Limes.

Province of Britannia · Founded 85 CE

Auxiliary fort south of what became Hadrian's Wall. The wooden Vindolanda tablets — Rome's oldest written documents from Britain — come from around our snapshot.

Today: An uninhabited Roman fort site near Hexham, England, on Hadrian's Wall's UNESCO frontier, and still an active dig with volunteer excavations every summer.

Province of Gallia Belgica · Founded 16 BCE by Augustus

Augusta Treverorum, Roman capital of northern Gaul. Later imperial residence and one of the empire's biggest cities. In 117 CE, a booming provincial capital.

Today: A living German city of around 106,000; its Roman monuments, including the Porta Nigra, baths, and bridge, form a UNESCO World Heritage Site standing throughout the modern town.

Province of Germania Inferior · Founded ~100 CE by Trajan

Colonia Ulpia Traiana, a Trajanic colonia on the Rhine named for the emperor. Fresh-built at our 117 CE snapshot — mostly veterans of the Rhine legions.

Today: Germany's largest open-air archaeological park, built over Roman Colonia Ulpia Traiana with full-scale reconstructed buildings, part of the UNESCO Lower German Limes.

Province of Achaea · Founded 44 BCE (re-founded by Caesar)

Provincial capital of Achaea, re-founded by Caesar over the ruins of the Greek city Rome had destroyed a century earlier.

Today: Uninhabited ruins in the village of Ancient Corinth, a few kilometers from the modern city of Corinth; excavations by the American School continue today.

Province of Achaea · Founded 1st c. BCE (Roman agora)

Under Rome but coasting on its glorious past. Hadrian would soon add his Library, arch, and Olympieion.

Today: Greece's capital and largest metropolis; the Acropolis and Ancient Agora are fenced UNESCO World Heritage sites within the living city.

Province of Achaea · Founded 8th c. BCE

Sanctuary of Apollo — still a working oracle in 117 CE, though its reputation was fading.

Today: An uninhabited archaeological site; the adjacent modern village of Delphi was relocated in 1892 to allow excavation, and the sanctuary is now UNESCO-listed.

Province of Lusitania · Founded 25 BCE by Augustus

Emerita Augusta, capital of Lusitania, founded for veterans of the Cantabrian wars. Its theatre, amphitheatre, and aqueducts are among Spain's best preserved.

Today: A living Spanish city of around 60,000, capital of Extremadura; its extensive Roman ruins, including the theatre, amphitheatre, and aqueduct, are woven through the modern town.

Province of Baetica · Founded 206 BCE by Scipio

Home town of Trajan and Hadrian. Trajan's expansions doubled the city just before our snapshot.

Today: An uninhabited archaeological park near Santiponce, Spain, just outside Seville; birthplace of Trajan and Hadrian, with its older quarter still lying under the modern village.

Province of Italia · Founded 181 BCE (Latin colony)

Adriatic gateway to the Danube — a booming port and one of the largest cities in Italy in 117 CE.

Today: A small living Italian town of around 3,000 sitting atop a largely unexcavated Roman city; its archaeological area and basilica are a UNESCO World Heritage Site.

Province of Italia · Founded 89 BCE (Roman municipium)

Prosperous northern-Italy city on the Adige. Its arena, built around 30 CE, was already old when Trajan died.

Today: A living city of around 258,000; the Roman arena still hosts a major open-air opera festival each summer, within a UNESCO-listed historic centre.

Province of Italia · Founded 1st c. BCE (Roman municipium)

Base of the Classis Ravennas, the Adriatic fleet, from Augustus onward. In 117 CE Ravenna sat directly on the coast — the shore is now 8 km east.

Today: A living Italian city of around 160,000; eight Early Christian and Byzantine monuments with famed mosaics are UNESCO World Heritage, woven into the modern town.

Province of Italia · Founded 42 CE by Claudius

Rome's imperial harbor. Trajan's inner hexagonal basin was finished just before our snapshot — you can still see its outline today.

Today: An uninhabited archaeological site near Rome's Fiumicino airport; the hexagonal basin of Trajan's ancient harbor still survives amid the modern town.

Province of Italia · Founded traditional 1215 BCE (Sabine)

Roman Tibur, a hillside retreat above the Aniene falls. Old sanctuary of Hercules Victor, favored by Rome's senatorial class. Hadrian's villa was still on the drawing board.

Today: A living town of around 55,000 near Rome, home to two UNESCO sites: the uninhabited ruins of Hadrian's Villa and the Renaissance gardens of Villa d'Este.

Province of Italia · Founded 7th c. BCE

Roman Praeneste. Home to the Sanctuary of Fortuna Primigenia — a vast terraced complex climbing the hillside, one of the most ambitious pieces of architecture the Republic ever built.

Today: A living Italian hill town built directly atop the ancient Temple of Fortuna Primigenia; the sanctuary's terraces underlie it, with a museum in the Palazzo Barberini.

Province of Italia · Founded 194 BCE (Roman colony)

Roman Puteoli, Italy's main port for eastern grain and luxury goods before Portus took over. Its Flavian amphitheatre — the third-largest in the empire — was newly built at our snapshot.

Today: A living port city of around 77,000 near Naples; Roman ruins including the Serapeo market and amphitheatre sit within the modern town, beside the active Solfatara volcano.

Province of Italia · Founded 2nd c. BCE (resort)

The emperors' favorite spa. Domed bath halls fed by volcanic hot springs on the Bay of Naples. Trajan and his court would have known it well.

Today: Largely submerged; much of the ancient resort now lies underwater in the Bay of Naples, protected as the Baia Underwater Archaeological Park and visited by divers.

Province of Italia · Founded 8th c. BCE (Euboean Greek)

The oldest Greek colony in Italy, home of the Cumaean Sibyl. By 117 CE its acropolis temples were already tourist attractions.

Today: An uninhabited archaeological park in the Campi Flegrei near Naples, including the Cave of the Cumaean Sibyl and acropolis temples, with no modern settlement on site.

Province of Italia · Founded 9th c. BCE (Etruscan)

Once the second city of Italy, home to a huge amphitheatre that later served as the model for the Colosseum. Its gladiator school was Spartacus's starting point.

Today: The ancient city's ruins lie in the modern town of Santa Maria Capua Vetere; its amphitheatre, the second-largest after the Colosseum, was the site of Spartacus's revolt.

Province of Italia · Founded 268 BCE (Latin colony)

Roman Beneventum, terminus of the Via Appia and starting point of the Via Traiana. Trajan's Arch here was dedicated in 114 CE — three years old at our snapshot.

Today: A living city of around 55,000 in Campania; the near-intact Arch of Trajan still stands astride a street in the modern town.

Province of Italia · Founded 600 BCE (Greek Poseidonia)

A Greek colony absorbed into Rome. Its three Doric temples — 500 years old in 117 CE — were already ancient monuments.

Today: An uninhabited UNESCO World Heritage archaeological park near Salerno, home to three of the best-preserved ancient Greek temples in the world.

Province of Italia · Founded 89 BCE (Roman municipium)

Roman Brixia, a northern-Italy city under the Alps. Vespasian's Capitolium — three temples in one — was newly built and dominated the forum.

Today: A living city of around 200,000; its Roman forum and Capitolium temple, part of the UNESCO "Longobards in Italy" site, stand in the historic centre.

Province of Italia · Founded 590 BCE (Insubres); Roman 222 BCE

Roman Mediolanum, the largest city in northern Italy. In 117 CE, a booming provincial hub — not yet the imperial residence it would become in the 3rd century.

Today: A major living metropolis of around 1.4 million; Roman-era remains like the Columns of San Lorenzo survive as isolated fragments within the modern city.

Province of Italia · Founded 268 BCE (Latin colony)

Roman Ariminum, the pivot of Roman north — the Via Flaminia met the Via Aemilia here. Its Arch of Augustus (27 BCE) and Bridge of Tiberius (21 CE) both still stand.

Today: A living seaside city of around 150,000; the Arch of Augustus and the Bridge of Tiberius, both still in everyday use, stand within the modern town.

Province of Italia · Founded 387 BCE (Syracusan Greek)

Adriatic naval harbor. Trajan enlarged its port; his commemorative arch was dedicated in 115 CE, two years before our snapshot.

Today: A living port city of around 100,000 on the Adriatic; Trajan's Arch still overlooks the working harbor it was built to commemorate.

Province of Italia · Founded 177 BCE (Roman colony)

Roman Luna, the marble port. All the white Carrara marble that clad imperial Rome shipped from here.

Today: An uninhabited archaeological park near the Tuscany-Liguria border, abandoned after its harbor silted up in the Middle Ages, with a museum nearby at Ortonovo.

Pannonia Superior · Szony district, Komarom, Hungary

Germania Inferior · Bonn, Germany

Moesia Inferior · near Svishtov, Bulgaria

Pannonia Inferior · Obuda, Budapest, Hungary

Britannia · Caerleon, Newport, Wales, UK

Iudaea · Kefar 'Otnay / Legio junction, near Megiddo, Israel

Africa Proconsularis (Numidia military district) · Tazoult-Lambese, Algeria

Arabia · Bosra, Syria

Syria · Rafniye, Hama Governorate, Syria

Moesia Superior · Kalemegdan, Belgrade, Serbia

Syria · Belkis, Gaziantep Province, Turkey

Moesia Inferior · Turcoaia, Tulcea County, Romania

Iudaea · Legio/Kefar 'Otnay, near Megiddo Junction, Israel

Germania Inferior · Birten, near Xanten, Germany

Moesia Superior · near Kostolac, Serbia

Germania Superior · Strasbourg, France

Britannia · York, England, UK

Iudaea · Old City, Jerusalem

Pannonia Superior · Vienna city center, Austria

Moesia Inferior · Silistra, Bulgaria

Cappadocia · Battalgazi, near Malatya, Turkey

Dacia · Alba Iulia, Romania

Pannonia Superior · Petronell-Carnuntum / Bad Deutsch-Altenburg, Austria

Cappadocia · Sadak, Gumushane Province, Turkey

Britannia · Chester, England, UK

Aegyptus · Sidi Gaber area, east Alexandria, Egypt

Germania Superior · Mainz, Germany

Pannonia Superior · Szony district, Komarom, Hungary