I'm not sure that this is true (ignoring the bit about blasting, which hasn't been a standard way to build metro lines for a very long time, of course); there was a lot found when London's Crossrail was built, say.
(While it's not made totally clear, I assume they're mostly finding stuff building stations, not tunnels. The tunnels are ~20m below ground, but the stations have to go all the way to the surface.)
Really, any old city, anytime you build anything you may find something. For instance, here's a supermarket with bonus Viking ruins in Dublin: https://www.atlasobscura.com/places/aungier-street-lidl-arch...
This is exactly right. Rome's subway is famously dug very deep (30-80 meters) so the tunnels run under the ruins, but each station requires an excavation down to tunnel depth.
Some photos of the "before" here:
https://www.thessalonikiguide.gr/metro-thessalonikis-mia-arx...
I only morn the loss of jobs that could have been part of the metro, if the wagons weren't robots.
Actually we have the same problem in Lisbon and Porto, the cards you can top up are company specific, only the monthly subscriptions work across companies.
Once again Romans taking "inspiration" from the Greeks :)
While visiting Vienna, there are ruins on display in Michaelerplatz (central Old City), so cool.
There definitely are instances of buildings being misaligned.
In my ancestral family home there was a door wat ground level, but originally it had a few steps to get to it; the outside ground had gone up by some 40cm with sediments over a century or so.
Of course elevated trains are not good for tourism. Not unless you're Elwood Blues and can get used to the noise.
It opened four months ago.
