So Humans went extinct in the future, they are completely gone, but their buildings are not. Now it's 10 million years in the future, and I want to know what could plausibly still be visible on the surface.
In the centuries preceding their disappearance, they had switched from concrete 'n steel to a material called handwavium. Handwavium is very resistant to erosion, no biological process breaks it down, it is much stronger than steel, and like gold, it is very hardy against the elements, and it doesn't corrode. It will not be wethered away in 10 million years. Most of any buildings is made from it, as it is deployed by 3D printing. Maybe with a superstrong metal beam inside it for support. Handwavium is used in everything in the future because through the (Handwave) process it can be easily recycled. Although skyscrapers would still collapse in 10 million years from just the stress of holding their own weight, and large/maybe medium buildings as well.
On top of that, they also build their buildings to be very stable and resistant to collapse from weathering, the elements, etc. Although weak points in the building and the stress of its own weight will still cause its demise eventually.
Now, let's take the city of New Atlanta(The city of Atlanta, Georgia), a very dense city with everything from skyscrapers to suburban neighborhoods. After 10 million years, how much of the city could still plausibly be visible on the surface? Could there be debris and household items littering the surface?