I have never seen a place so small contain so much history. The city of Yerevan alone is said to be over 3000 years old, and Armenian civilization as a whole predates that by at least another millennium, and since then, you can see such a mix of culture and history within every town, city, or village. Case in point, It has been part of an ancient Armenian empire, medieval Georgian kingdom, part of Timur's empire based out of modern day Uzbekistan, part of the Ottoman Empire, and ultimately the Soviet Union before becoming its modern independent state, and each one has left a little something behind. Not to mention, Christianity in Armenia predates that in Europe as well as everywhere else in the world, so many of the oldest churches ever constructed are scattered about across the countryside. Even Italy with all the history of the Roman Empire can't compete with it.
Yes, I understand this choice may seem to be a cop-out and to lack creativity, especially as I try to highlight places off the beaten track. But it is Rome, and if I am honest about history, I cannot leave this out (and, I admit, I was still incredibly excited to see it all despite the crowds of tourists). Within Rome, it was particularly interesting how all the famous site were preserved. Usually, in other ancient cities, most of the historical buildings will either be in the historic city center or on the outskirts, away from modern development, but in Rome, it was as if the modern city had just grown around and in between the old structures. You could be walking down the streets, pass by a few hotels and restaurants, and then come upon the Colosseum.
What makes Russia's preserved historical sites so interesting in the huge variation of cultural diversity. As I have said before, Russia is comprised of over 100 different ethnic groups, each with their own language and with their own history. You have the old history of Kievan-Rus in the west, Tatar history along the Volga, as well as countless others in the Caucasus, Urals, and across Siberia. Most of all though, there are so many significant modern historical sites to see in Russia as well dating back from the Soviet era. Many of which (including underground bunkers and formerly restricted cities), were not even available to the Russian public until the 1990s.