Yes, some old places, eg Troy have about 7 levels of buildings all built on top of the ruins of the older ones. Some places are abandoned, some of the stones are taken by local people for building new buildings and the remains eventually get covered by soil, grass, and eventually shrubs and then trees. We recently went to a site known for it's fossils (or so my friends husband said) but when we got there it was 90 per cent grass, when friends husband was last there (about 15 years ago) all you could see were fossils. In about 100 years it could well have small tress on it!