ROME (AP).- Italian officials unveiled new discoveries Thursday in an ancient Roman luxury complex filled with priceless mosaics, elegant porticos and thermal baths. The 1,800 square-meter (2,000 square-yard) complex, dating from the 2nd to 4th centuries, has been excavated intermittently since 2004, when the ruins were accidentally discovered during the renovation of a Renaissance palazzo that stands above them. In the latest excavation, which began in March, archaeologists uncovered a palatial room decorated with precious marble and a colorful mosaic made with half a million tiles brought from all over the Roman Empire.