A day and a half was not enough to see Rome. I did two guided tours, but there was so much to take in. I hope I tell you the right information about these places...
I believe this is the Arch of Constantine.
I do know for certain this is the Colosseum! It is right by the street, and has become discolored due to the pollution. Also, only one third of the building remains because of earthquakes.
I thought this place was fascinating. Below you can see underground passages where the animals were kept before the fights. It is not there now, but there was a wooden floor that covered this part, and it was covered in sand - partly for traction of the gladiators, but also to soak up the blood.
When the stadium was finished, there was a 100 day festival where 2,000 men and 9,000 animals were killed. The animals came from all over the world - lions, tigers, bears...
This is Palantine hill - where the city of Rome was founded. I forget whose palace was here (Agustus?), but this was part of the baths, and an private arena for sporting events.
This is the Forum. This was the city center of Rome. The most important temples and courts were here.
Here is another view from outside the Forum. It is mostly ruins now.
This is the House of the Vestal Virgins. The girls were selected at age 10, and served for 30 years. If the girl failed to keep the vow of chastity - they were taken to a crypt and buried alive with a lamp and a loaf of bread.