There are plenty of ancient places that are easily accessible and above ground.
Why is it however that a vast amount of other historic cities and areas end up multiple feet under the ground? I get that in some places you could have a flood or landslides or things like this but what about all the others? How does a bustling city go from well populated to 3 feet under ground 500 years later?
This very common question came up just yesterday. You can find links there to several replies. There are also many others if you go searching.