Rome's former emperors ruled the world in a larger-than-life way. And to make sure no one would forget, from centuries ago until now, an intact host of intricately designed arches and towers are scattered among the ruins.
When entering the Forum from the east along Via Sacra, you pass under the Arch of Titus which was built in 81 A.D. following reconquering the Jews in Jerusalem. The inner-archway has detectable carvings of Roman soldiers carrying off spoils from the Temple and Judea. I overheard a tour guide explaining how these have significance with the book of Revelation and prophecy fullfilment...that Rome will someday return the haul to Jerusalem.
If entry from the west forum was still permitted, you'd pass under the Arch of Septimus Severus which was built in 203 A.D. to commerate the triumphs of his 10th anniversary as Emperor. After his death, fueding family members altered the original having names stricken from the monument. During my visit, the arch was sectioned off prohibiting close-up, indepth viewing of the intricate frieze murals.
The Arch of Constantine, built 315 A.D., likely receives top billing within shadows of the Colosseum, but a study-guide summarized the construction as an egotistical knock-off effort by Constantine to declare himself the ultimate center of Roman history both passed and present. He raided other projects of Trajan, Hadrian and Marcus Aurelius using statues/sculptures around his own self-centered creations - therefore, creating a work that combines architectural styles and historical depictions. Still, the work is a sight to behold as close as barriers allow!
Trajan's Column, located on the northern rim of the remains of his forum, was erected in 113 A.D. with spiraling friezes from bottom to top of the 40-foot tower depicting scenes from his two greatest campaigns against modern-day Romania. Honoring Marcus Aurelius after his death, a replica tower was erected in 180 A.D. that stands in the Piazza Colonnaection off Piazza Della Rotunda. Eyewitness Rome Guide gives detailed accounts describing differences and similarities between these monumental towers while also pointing out that the Pope's replaced both crowning statues - Trajan for St. Peter, Marcus for St. Paul.
Craftsmanship of the arches is one thing, but the intricate detail and designs used on the towers is simply mind-boggling. Close-up viewing is almost dizzying with the upward-spiraling progression of the work. Casts used for creating the tower would certainly be worth checking out at EUR's Civilta Romana museum.