Hellenistic cremation burial found in Istanbul train station
thehistoryblog.com
thehistoryblog.com
I guess maybe Rome comes close but even then it doesn't have the sheer variety of Istanbul
More layered? I doubt it. Byzantium was much more stable for centuries, Rome was officially and unofficially conquered several times and mutated fashions very often. Obviously the differences might look more striking in Istanbul because of the Ottoman conquest.
If the amount discovered is immense, some of it will make it to light of day, and a considerable amount will simply be destroyed, as the construction will continue despite the find. To my limited knowledge, once an artifact is found, it’s illegal to continue construction.
When the discoveries are small, the news of it will be suppressed and construction will continue normally. Some artifacts usually end up in the possession of the site manager or the owner of the contracted conglomerate.
There used to be independent journalism uncovering such events, this is no longer the case.