We've had hints that this sort of thing was going to be found ... I hope we get more details on this one from the Scotsman:

Archaeologists have discovered an ancient Byzantine port in an area of Istanbul that was to be an underground station.

What might be a church, an old gate to the city and eight sunken ships have been found so far.

Not much more detail in an AP Wire report, other than they're calling it the 'Port of Theodosius' ...