Aytac said the restoration of the 112-step cistern from the Urartu period was completed in 2021 and opened to tourism.
He also noted that Harput Castle contains many smaller cisterns but only two large stepped cisterns, adding the first, known as the dungeon where a Crusader king was imprisoned during the Seljuk period, was opened to tourism in previous years.
"The restoration of the second stepped water cistern has recently been completed," Aytac said. "It is a 4-meter diameter cistern carved into natural rock, descending 30 meters down with 52 steps."
The cisterns are about 2,800 years old and were used for water supply by subsequent civilizations, he added.
"The significance of this site (cistern) is that it is one of the most important and largest cisterns carved into natural rock in Türkiye. When the water ran out, it was used for food storage."