The whole CITY is ontop of an archeological dig.
Some of the modern buildings literally have glass sidewalks to allow the public to see the archeological buildings below. (the Athens Stock Exchange for one)
The Athens metro was YEARS behind schedule because of "dig, dig, dig, stop, study, excavate, dig, dig,stop, study, excavate,dig, stop, study, excavate, dig, (repeat...)
You really should wonder how much of this stuff is in private hands because somebody was doing something in their back yards.
Just check out the shops in Russell Square across from the Bristish Museum in London. Plenty of it for sale there.