Before Budapest became Budapest, it was an important strategic city/fort for the Roman Empire. It's name was Aquincum, and it was the capital of the border province of Pannonia Inferior, protecting Rome from the barbarian tribes across the Danube. Empreror Marcus Auralius may have written some of his famous Meditations here. By the end of the 2nd century AD the town had between thirty to forty thousand residents.
aerial view of part of the civil city of Aquincum
When the Roman Empire collapsed, the old Roman city was eventually buried and only discovered again in the 18th century. There is a large military fort a few miles away from the town, and near the town is also an amphitheater larger in land size than the coliseum in Rome (though in FAR worse condition).
My family spent an enjoyable afternoon walking around the ruins of the civil town. In the photo above you can see the hot water plumbing under the floor of one of the buildings. There were baths all over the place, both public and private ones, showing just how much bathing meant to the Romans.
And here is a shot of me taken by my eldest son Anton. Rome is my favorite period from history, though I tend to prefer the Republic to the Empire. I hope my sons will come to love this history as much as I do. My younger son tried to read the brilliant Rome series by Colleen McCullough, but he was just too young for it for now. If you haven't read these books, I can't recommend them enough to anyone who loves history or historical fiction.