I haven't done what I consider a lot of travelling, compared to some people, but in my mind one the best places to see ruins is in Sicily.
One of our first stops was at Segesta where we had to take a bus to the top of the "mountain" to view the ruins. Above are the remains of the amphitheater and the view from there is amazing. I posted photos of the view and other things on my last ABC Wednesday "S is for Sicily" post. Feel free to pop over to take a look.
Our next stop was at Selinunte where we viewed more ruins of Greek temples.
We continued on to Agrigento and strolled around the Valley of the Temples that is located outside of the modern city. I like the shot (below) of one of the ruins because you can see the modern city in the background.
Another stop was at Villa Romana at Piazza Armeria. Here is a shot of the marble toilets, considered quite modern at the time, that the women used.
Finally, I've included my photo of the Teatro Greco in Taormina. We spent a long time here, even climbing way up to the top and behind the seats. The view of the Mediterranean was stunning and you can see Mount Etna across the way. We actually saw fire and smoke coming out the top of famous volcano and it erupted the night we were there.