He designed some of the most significant structures of antiquity such as Trajan's Forum in Rome with Stadium, Triumphal Arc and Trajan's Column. His markets are the finest-known example of modular commercial construction in concrete.

He also built public bath's , port facilities, a bridge across the Danube, and the circular 'Odeon' Theater in Rome. When he rejected emperor Hadrian's architectural ideas he was banned and executed.