What Roman column in Rome commemorates Emperor Trajan's victory in the Dacian Wars?

The Roman column in Rome that commemorates Emperor Trajan’s victory in the Dacian Wars is Trajan’s Column.

Completed and dedicated in AD 113, the monument stands in Trajan’s Forum, north of the Roman Forum. Its continuous spiral relief depicts Rome’s campaigns against Dacia in 101–102 and 105–106, including marches, ceremonies, bridge-building, battles, and the defeat of the Dacian king Decebalus. The monument was probably designed under the supervision of Apollodorus of Damascus.

The column’s shaft is about 30 metres high, with a frieze winding around it 23 times. Inside, 185 steps lead to the top. Trajan’s ashes were later placed in the column’s base, while the original statue of the emperor was eventually replaced by a statue of Saint Peter in 1587.

A common mix-up is the Column of Marcus Aurelius, another Roman victory column with a spiral narrative, but it commemorates the emperor’s wars against Germanic and Sarmatian peoples rather than Trajan’s Dacian conquests.