The Roman Forum and it makes sense to go there. In general, I did not like Rome very much, but if I go there, then I will look at old times of this kind. I liked the forum more than the Colosseum. Even in the week of free visits, do not forget to take a free ticket first. And if, for example, there are three of you, then the three of you come for tickets, because at the checkout they require you to present all those who need a ticket.