From the History Blog
The construction of Rome’s new metro line has encountered yet another archaeological marvel: a Republican-era aqueduct dating to around the 3rd century B.C., likely a section of the first aqueduct built in Rome. Archaeologists found the structure during construction of a ventilation shaft under Piazza Celimontana on the Celian hill. The shaft’s 18-meter (60-foot) depth allowed them unique access to the 3rd century layers of the city. Without the bulkheads keeping the water from flooding the site, it wouldn’t have possible to excavate anywhere near that deep.
For more, check out the History Blog.
Here are a few dudes walking inside