It took the city of Amsterdam 20 years to build a central subway line, but they've done a magnificent job in establishing an efficient means of transport.
During the process many archaeological items were found, including very many coins. The nice thing is that all of those finds are documented on the following website:
I think I found one for artefacts (coins included) found during the construction of Rome's metro system, which is extremely limited compared to most other European metropolises (primarily because much of Rome is built on, well, more of Rome). Can't remember the site now though.
