Entering the exhibition space of relics at the Imperial Citadel of Thang Long, many people might notice a large artifact in the exhibition area of the Ly Dynasty. It is the "La de chim phuong" roof tile, a National Treasure. The artifact is a large roof tile, that was used to decorate the center of the roof. It was discovered in 2003 at the Archaeological Site at No. 18 Hoang Dieu street. The artifact was recognized as a National Treasure by the end of 2021. When discovered, the base of the tile was broken. The leaf pattern on the tile was cracked. After being restored, it was brought into the exhibition area. This is also an original and unique artifact, making an important contribution to the study of art during the Ly Dynasty in the 11th and 12th centuries./.