One of the main points behind overseas travel is to experience places quite different from home. Travel to Europe (and other places) allows a brush with certain significant historical periods simply not available in real life in Australia. Take the Roman Empire, for instance. The largest and most powerful political entity in its heyday - but it completely bypassed Australia.
So when we go to Europe, we sometimes visit ruins (Roman or otherwise). This gives US a connection with a distant history (physically and temporally) and also brings it to life for the kids. On our last trip, we took the opportunity to visit the Roman ruins at Conimbriga, Portugal; the Iron Age settlement of Citania de Briteiros, Portugal; the Moorish city of Medina al-Zahara, Spain and the Roman city of Italica, Spain.
You do have to be careful what you say to your kids, and how you say it, because everywhere we went Bendy would walk around the sites loudly declaiming about just how much the Romans had ruined it (whether or not the Romans had ever been there!). "Roman Ruins" transformed into "The Romans Ruined It"!