I was thinking about Rome and there is one place that’s a 17th century church, on top of 14th century monastery on top of a 1st century apartment. And if you go to the Forum section it’s visibly below the surface of the current city.
For the fact that the city has been active for thousands of years, how do things end up getting buried? Does that mean the elevation of the city is higher now than it was in 0 AD?
Not everything—high elevations like hilltops and mountain slopes tend to erode away, while the eroded silt accumulates in lowlands and flood plains. It’s just that ancient cities (and their surrounding farming communities) were overwhelmingly built near rivers and flood plains.