Final answer:
Trajan's Column was built by the Romans to commemorate Emperor Trajan's victory in the Dacian Wars. It is adorned with a detailed frieze depicting the wars, showcasing Roman military achievements and construction skills.
Step-by-step explanation:
The monument built by the Romans to celebrate a military victory is Trajan's Column. Erected in 113 CE, Trajan's Column was constructed to honor Emperor Trajan's triumph in the Dacian Wars. The column stands 35 meters high and is wrapped in a spiral frieze that meticulously depicts the Dacian Wars with over 2350 figures, providing a detailed visual record of the Roman army and its victories. This piece of architecture, showcasing Roman construction skills, was designed both to impress and inform the public about the power and success of the Roman military.