" a 21-mile underground journey to Rome"

ROME — In a verdant valley east of Rome, Fabrizio Baldi admires a forgotten stretch of a two-tier Roman aqueduct, a stunning example of the emperor Hadrian's 2nd century drive to divert water from rural springs to his ever-thirstier capital.

But Baldi, 36, is less interested in the graceful arches than in where the aqueduct's span ends, hidden in a wooded slope across a stream, halfway up the side of the valley. Scrambling through thick brambles, he comes across a large hole in the ground that appears to be the start of a tunnel.  "This is where the water poured off the aqueduct and started a 21-mile underground journey to Rome."

Baldi is one of about 80 amateur speleologists who spend their weekends crawling down underground channels with laser scanners and GPS in an effort to conclusively map the city's network of 11 ancient aqueducts for the first time in modern history. In doing so, they have turned up underground stretches that nobody remembered.

http://www.latimes.com/world/la-fg-roman-aqueducts-20140101,0,2669673.story