Ancient Rome liked to build the Arc de Triomphe to show off its achievements. The Arc de Triomphe, built in 315 AD, commemorates the reunification of Rome by Constantine the Great. It is also one of the three triumphal Gates left by the city of Rome. The Arc de Triomphe was founded by the Romans, but now it is the Paris Arc de Triomphe ordered by Napoleon in 1806. When it comes to the Arc de Triomphe, the first reaction is the Arc de Triomphe in Paris.