Scientists were amazed to stumble across some of the oldest glass kilns in the world near Mount Carmel in Israel.

An Israel Antiquities Authority inspector discovered the kilns last summer as a railway was built. The inspector found chunks of glass, a floor, and a layer of ash, according to an Israel Ministry of Foreign Affairs statement.

Officials immediately halted construction so that an archaeological excavation could begin, which is when they found the kilns.

The kilns could burn up to 2,200 degrees Fahrenheit. They would have been used to melt beach sand and salt for weeks to create raw glass. Then, the glass was broken into smaller pieces and used by workshops to create glass pieces.

The light green Judean glass was likely about 1,600 years old, and would have been used in the Roman empire.

Ian Freestone, a University College London professor, called it a “sensational” discovery that would have provided evidence that Israel was a production center that distributed glassware throughout the Mediterranean and Europe, according to media reports.

“This is a very important discovery with implications regarding the history of the glass industry both in Israel and in the entire ancient world,” Yael Gorin-Rosen, head curator of the Israel Antiquities Authority Glass Department, said in the statement. “We know from historical sources dating to the Roman period that the Valley of ‘Akko was renowned for the excellent quality sand located there, which was highly suitable for the manufacture of glass. Chemical analyses conducted on glass vessels from this period which were discovered until now at sites in Europe and in shipwrecks in the Mediterranean basin have shown that the source of the glass is from our region. Now, for the first time, the kilns have been found where the raw material was manufactured that was used to produce this glassware.”