Aqueducts were costly public works ... Today it is used for irrigation and to supply some of the most beautiful fountains in Rome. The road to Praeneste (modern-day Palestrina) passed under ...

We asked Aicher, author of "Guide to the Aqueducts of Ancient Rome," about ... Or they could divert it to industrial uses or irrigation, where cleanliness was not as important.

It's the final leg of the massive Colorado River Aqueduct: the 13-mile-long San Jacinto tunnel, bringing up to 1,700 cubic feet of water per second underneath one of Southern California's tallest ...