A lady I met in Rome told me that if she could see one museum for the last time, it would be the Galleria Borghese. This convinced me that I needed to go see the museum which is located in the Villa Borguese Gardens. You could spend a whole day at this park and the museum because there is so much to see. Below is a map of the park and some pictures of the sculptures you can see in the area.
To visit the Galleria Borghese museum which is within the park, I highly recommend buying a ticket online the day before or earlier. It will cost 13 Euro in total and it is almost necessary because tickets sell out. You get to choose what time you want to go and I recommend showing up at least 30-45 min prior to the time scheduled because you have to wait in line to get a physical ticket, then if you want an audio guide for 5 Euro, then you have to wait in another small line, then you have to wait in a longer line to check in your backpacks and purses because these are not allowed in the museum. However, after you get inside, the masterpieces will awe and amaze you. Here are some pics I took inside.
This is just a brief highlight of the beautiful art you can see here but I highly recommend going if you are in Rome.