ideas and government, military. the roman military was a citizen militia that were mainly wealthy people, the main soldiers were the legionaries which carried to javelin for long range combat, and a sword along with a knife. they came up with artillery which shot darts that would blow through the enemy's.
engineering and architecture, the colosseum. the colosseum was a very large stadium where the plebs would go to do a bread and circus, a mix of gladiators fighting to the death and gory animal battles. in some cases the romans would use wild animals in no chance fights where the prisoners would face lions and tigers, the romans would use a set of pulleys to haul the cages up to the stadium, from the basement.
religion, rise of christianity. Jesus was a jew, he believed that god was his father and that you should admit your sins and let god take over. his followers believed in him and spreaded his preaching, he made a new religion called christianity, the romans hated this religion, they treated the people horrible and when the romans became christians, they treated the other people badly.
art, statues. the romans were copycats, they copied the chariots from china, they would make sarcophagus which were considered egyption. But what I am talking about is what they copied from the greeks, statues buildings all of that stuff. First is the statues, when the romans copied, they copied but also made a few changes, greek statues were flawless, they had perfect bodies while the romans added warts and stuff like that.