TEHRAN (FNA)-Archeological studies revealed that the underground water network in Iran's ancient city of Persepolis is as old as the Achaemenid capital.
"An Achaemenid residential layer has been found in Persepolis along with four ancient wells, which were dug at the same time or a little while after the city was built," said head of Persepolis archeology team, Afshin Yazdani.
"There is no convenient space for workers to sit beside wells or dig in a conventional manner," he said, adding that they may have used special digging methods, press tv reported.
There are three more wells to be studied until the end of the new excavation phase, which started on Dec. 5th, 2008.
Darius I established Persepolis in 518 BCE as the new capital of the Achaemenid Empire after Pasargadae. The importance and quality of the monumental ruins has made it a unique archaeological site.
Located 70 kilometers northeast of the city of Shiraz in Fars Province, Persepolis was registered on the UNESCO World Heritage List in 1979.