Public death was staged for spectacle on this ground

An amphitheatre rose on Nero's drained lake

You are standing on the floor of the Colosseum itself, or within a few strides of its outer wall — the coordinates place you almost exactly on the amphitheatre. Vespasian ordered its construction here in 72 AD, on ground that had been the artificial lake of Nero's pleasure grounds, and his son Titus opened it in 80 AD with games that reportedly ran a hundred days. Tens of thousands packed the tiered seating around you to watch gladiatorial combat, staged hunts, and executions — the amphitheatre's entire purpose was public death, delivered as spectacle, on this spot.

Just beyond the arena wall, barely a hundred metres off, stood the Colossus of Nero, a 30-metre bronze statue from Nero's vestibule that was later re-carved into a sun god and dragged to the amphitheatre's edge — by one persistent theory, it is this statue's presence that gave the Colosseum its name.

A short distance west, the conical fountain known as the Meta Sudans once marked the junction of processional roads into the valley, its basin "sweating" water for centuries until it was demolished in the 1930s. Directly beside it rises the Arch of Constantine, raised by the Senate in 315 AD to mark Constantine's victory at the Milvian Bridge, straddling the old triumphal route where victorious generals once marched their armies past this exact ground.

Palaces, processions and a triumphal arch surrounded it

A few minutes' walk northwest, Domitian's sprawling Flavian Palace crowned the Palatine, completed in 92 AD as the seat of imperial power. Nearer still, Nero's first palace, the Domus Transitoria, burned in the Great Fire of 64 AD — the disaster that gave him the excuse to build the vast Domus Aurea across the valley to the east, a landscaped complex of lakes and pavilions that swallowed the hillside after the flames died down.

The Via Sacra, Rome's most solemn processional street, ran along this valley toward the Forum, staged for the pageantry and brutality of the Roman triumph — the humiliation of captured enemies paraded past crowds before the Colosseum even existed. The Arch of Titus, standing where the Via Sacra crests the Velian ridge, still carries relief panels of the sack of Jerusalem in 71 AD, spoils and captives rendered in marble.

Closer to the present, the metro station Colosseo, opened in 1955 on Line B, turned up 28 Republican-era wells and the remains of a bath complex during construction — two millennia of buried Rome surfacing again under twentieth-century engineering. And on Via San Giovanni in Laterano, leading east from the amphitheatre, a stretch formally became "Gay Street" in 2007, a modern LGBT-friendly quarter layered directly onto the ancient street grid.

Volcanic rock underlies the arena and its ruins

Underneath all of this — the arena, the palaces, the metro tunnels — lies Quaternary tephrite and basanite, volcanic rock laid down by the Alban and Sabatini volcanic districts that once dominated this landscape, with older Cenozoic volcanic material beneath that. It's this volcanic tuff and the layered soil above it that made the seven hills defensible high ground and gave Roman builders their travertine and peperino stone. To the west, within Campitelli's tangle of streets, Piazza Campitelli and the church of S. Maria in Campitelli have been photographed for the Roman national library's archive for generations, a quieter Baroque counterpoint to the imperial ruins nearby. And half a kilometre off, the Roman Forum and its Curia, the Lacus Curtius, and the Mamertine Prison — where captured enemies were said to be strangled after being paraded through the streets you are standing near — complete the ancient civic core that this amphitheatre valley always sat beside, never apart from.