March 13, 2011, 7am PDT
The ancient irrigation networks lying below Phoenix could offer a solution to the sprawling desert city's water problems.
December 13, 2009, 1pm PST
Irrigation canals dating back to the year 1200 B.C. were discovered in Arizona this year, answering a long-asked question about how natives were able to farm the arid land.
October 16, 2003, 8am PDT
World Monuments Watch has released a list of the world's 100 most endangered sites.