I know that Colosseum has way more arches, (I am not stupid). I did my best to make (what I think) a good representation of the Colosseum.
Printer:
Da Vinci 1.0
Rafts:
Doesn't Matter
Supports:
Yes
Resolution:
best you can do
Infill:
10%
Notes:
I used PLA
I used Tinkercad
What I did is I started out by making a tube. I then mad arches and used them to create the arch pattern. I then duplicated the tube to form the main part of the Colosseum. I then cut off a part of the tube with arches and that made the part that sticks off the Colosseum I then made the inside part of the Colosseum by using a smaller tube and 3D triangles to finish the inside.