It is a plastic reconstruction, at the Trajan's Markets, depicting one of the most imortant events of the ancient Roman time. From the name you understand well how the triumph was a real event, well-studied by the emperors, consuls or generals that agreed to increase their personal glory and that of the whole of Rome.
A triumph was a true parade, perhaps even enriched by elephants that were carried out to show the roman citizens the fruits of a war. Of course, wars which were won! The war was the best propaganda instrument that had all of the political figures of the foreground to increase their popularity and their power. To win a war, showing all the prisoners captured (therefore, new slaves, new gladiators, new labour), the treasures and the riches (from the weapons to the ornamenta the various piled on from the litters of wood) meant to increase the political weight. The triumph was also a time of joy and fun, the moment in which the civus romanus (roman citizen) felt himself as part of a community and a civilization capable of conquering the world. In the republican era, chock-full of wars, even civil, the triumphs they were not numbered more! Moreover, because of this fun-loving spirit, the legion has felt free to taunt, jokingly refers to their general. It tells the story of how Caesar himself, returning to Rome after his victories, in the moment of triumph it had been also heavily, almost insulted by his own legionaries! Reading Svetonio we know that the soldiers who fought for Caesar alluded to the presumed homosexuality of their general singing "Caesar subdued the Gauls, Nicomedes Caesar behold, now Caesar triumphs, who subdued the Gauls, while Nicomedes does not triumph, even though he subdued Caesar".
The written sources describe how the crowd, who attended joining the triumph, got enraptured when on the scene appeared the king defeated, the heads of those enemies who had dared to challenge Rome! To avoid this harrowing time, many of the kings or rebels defeated by the romans, preferred to commit suicide rather than suffer the shame of a triumph celebrated in Rome. Even the emperors organized the great triumphs, actually more than one (Augustus, for his political propaganda, won three wars and so he celebrated multiple triumphs). Moreover it is true that this special public celebration could be used to gain popularity, giving for example important military and political roles to people who, just in case of emergency, could help the emperor. Augustus, according to Svetonio, "Was very generous in distributing honors to military valor: he decreed complete triumph to more than thirty military commanders, to many more he assigned the triumphal insignia". Some maybe overstated as Trajan who, it is said, to celebrate the victory against the Dacians not only organized a great triumph, but, also, he opened the buildings for show and entertainment for 120 consecutive days (probably). When someone knows how to celebrate himself...