The national archeological expedition recently discovered a gigantic building built with large-size hewn stones that date back to the Roman era, Syrian Arab News Agency (SANA) said Wednesday. The building, the thickness of its walls up to 1.5 meters, was found at Qumet Nibal site in the northeastern province of Raqqa, said SANA. Ibrahim Kheir Bek, head of the archeological department in the area, told SANA that the excavation unearthed a 6-meter-long entrance to the building, adding that works are still underway in the site. A day earlier, the national archeological expedition discovered a mosaic dating back to the 6th century A.D. in northeast Syria, SANA said, adding that the rectangular mosaic was found at Hwaija Halawa site on the banks of al-Assad Lake in Raqqa province. Ayham al-Fakhri, head of the national expedition, was quoted by SANA as saying that the expedition uncovered 58 square meters of the mosaic with various colorful geometric shapes.